M Series Plus C-Flex CPAP Machine with SmartCard Module

Product Features

Specifications

This Product Includes...

• REMstar Plus M Series Device
• 6 ft Flexible Tubing
• Carrying case with padded shoulder strap
• Power supply
• AC Power cord (3ft)
• Reusable gray foam filter
• Disposable ultra-fine filter
• Patient User Manual
• Provider Quick Set up Guide
• SmartCard Module
• SmartCard

Product Specifications

M Series Plus C-Flex CPAP Machine with SmartCard Module

	M Series Plus SM 339.00	Transcend II Travel 449.95	PR 60 Series Plus CPAP 295.00
Basic Features
Manufacturer This is the company that produces the product being compared.	Respironics	Somnetics	Respironics
Type This identifies the machine as continuous, auto adjusting, or bilevel operation. This does not identify whether the machine automatically adjusts pressure. Auto adjusting refers to APAP, whereas BiPAP Auto is differentiated using the Auto Pressure Adjustment property. BiPAP machines are defined further using Spontaneous or Timed properties. A CPAP machine blows one constant pressure of air into your passageway throughout the night. Your ideal pressure was determined during your sleep study. A BiPAP machine delivers two separate pressures of air; One when the patient inhales and a separate pressure when they exhale. The machine alternates between the two set pressures to help optimize your sleep apnea treatment. An APAP machine automatically adjusts on a breath by breath basis to blow the minimum pressure needed to keep your airway open during sleep. This allows your machine to provide you with your ideal pressure nightly.	CPAP	CPAP	CPAP
Warranty Warranty is the length of time that the manufacturer will guarantee a product to be free of defects. Warranties vary in length depending on manufacturer, but generally all machines come with a 2 Year Warranty.	2 Years	2 Years	2 Years
Sound Level This is the level of sound the machine produces at a pressure of 10cm, standing 1 meter away or roughly 3 feet from machine. Measured in Decibels, the values also indicate whether the machine is considered a "quiet CPAP"; see Quiet property.	31-dB	29 dBA	29 dB
Quiet This identifies which machines have a decibel rating of 29 and lower. This does not account for use with the humidifier attached, which could supply additional volume that can muffle or amplify sound. This property does not account for noise that travels through the CPAP tubing, seemingly sounding louder than the measured db rating.	No	Yes	Yes
Manuals Included This indicates which manuals are included with the purchase of a CPAP machine. Most all machines come with a patient manual; also called 'user manual', which may or may not have pressure setting instructions. Some machines come with both the patient and quick setup guide or both patient and clinician manuals.	Patient/Quick Setup	Patient/Quick Setup	Patient
Dimensions
Travel Sized Looking to travel? We have found some machines are easier to travel with than others. These smaller and more lightweight machines are still robust enough for constant daily use as well as travel.	Yes	Yes	Yes
Under 3 lbs This measures only the weight of the machine and does not include total weight of power cables, bag, additional batteries or non-built-in humidifiers.	Yes	Yes	Yes
Machine Weight This is the actual weight of the CPAP Machine without any accessories, power cord, or humidifier. Machines with a weight 3lbs or less are also identified in the Under 3 lbs property.	2.2 lbs	0.94 lbs	2.2 lbs
Entire Weight This is the combined weight of the machine, heated humidifier, power cables, bag and hose.	5.5 lbs	2.4 lbs	6 lbs
Entire Size This is the combined dimensions of the CPAP with the Heated humidifier.	8.25" x 8.2" x 4"	6.1" x 3.5" x 2.8"	6.5" x 10.75" x 4"
Entire Package Size This is the size of the CPAP with Heated Humidifier in its travel bag.	13" x 10" x 5"	9" x 4" x 10"	8 " x 14.75" x 8.5"
Machine Size Only Measures the overall dimension of the machine only. Machines with a built-in humidifier are marked NA and must refer to Entire Size dimensions.	7.5" x 5.0" x 3.1"	6.1" x 3.5" x 2.8"	7" x 5.5" x 4"
Humidifier Features
Heated Humidifier This indicates which heated humidifier works best with the listed CPAP machine. In some instances, Built-in is used to describe a machine/humidifier combination system. The Fisher and Paykel HC150 was used for machines that do not have an integrated or built in humidifier system.	M Series Heated	HME Waterless Technology	System One 60 Series
Built-In Humidifier Identifies which CPAP has a humidifier that is built into the CPAP. Built-In humidifiers cannot be separated from the CPAP machine.	No	No	No
Heated Humidifier Type This property identifies how the machine incorporates a Heated Humidifier. Build In humidifiers are built into the CPAP machine and cannot be separated from the machine. Integrated humidifiers connect directly to the CPAP machine and they can only be used with compatible CPAP machines. With Integrated� humidifiers, the CPAP machine, can be separated and used without the humidifier. CPAP machines that do not have a built in humidifier and do not have an integrated humidifier option have to use a Stand Alone humidifier as the machine's heated humidifier option. Stand Alone� humidifiers can be used with any machine and connect to the CPAP machine with an additional hose.	Integrated	Integrated	Integrated
RainOut Reduction Manufacturers are finding ways to reduce the amount of water that collects in the CPAP hose when using a Heated Humidifier. The Rainout Reduction feature varies by manufacturer and machine and can be anything from an integrated heated hose, to technology that measures the humidity at the mask and adjusts the humidity to reduce rainout.	No	HME Waterless Tech.	60 Series Heated Tube
Integrated Heated Hose This indicates that the machine has an integrated heated hose option to enhance humidification and reduce rainout. An integrated heated hose draws its power from the machine itself and does not have a separate power cord and is adjusted through the machine settings.	No	No	Yes
Pressure Features
Auto Pressure Adjustment This property defines whether the machine automatically adjusts pressure to meet the needs of the CPAP user on a breath-by-breath basis. All APAP machines are defined as 'Auto Adjusting', but some BiPAP's also use an Auto feature on both the IPAP and EPAP. If not marked, Yes, assume the machine does not have AUTO capabilities.	No	No	No
Pressure Range A CPAP (Constant Positive Air Pressure) delivers continuous airflow at a prescribed pressure at 4cm to 30cm. APAP operates between a range and BiPAP machines are a mix of ranges and constant pressures. This pressure is measured in centimeters of water pressure (H2O) and 4-20cm is average pressure range on most CPAP machines.	4-20cm H20	4-20 cm	4-20cm H20
EPAP Pressure Range This Property lists the operating range for the Exhalation Positive Airway Pressure (EPAP). This is the pressure setting used when you exhale. EPAP is always lower than the IPAP (inhalation) pressure, making breathing out easier and more comfortable.	NA	NA	NA
Easy Breathing Pressure Relief is a feature that lowers your therapy pressure to help with difficulties breathing against the machine's airflow, providing a more comfortable and natural breathing pattern. Assistance can occur on the Exhalation, on the Inhalation, and on both exhalation and inhalation at the same time.	C-Flex	No	C-FLex
Ramp The Ramp feature allows the user to start treatment at a lower pressure to fall asleep with, gradually raising the pressure over a set time. This is a comfort setting and can set from 0 to 45 minutes on most CPAP machines.	Yes	Yes	Yes
CPAP Mode This property defines whether the machine is capable of continuously blowing a constant pressure. All CPAP machines are defined as 'continuous', but some BiPAP's and APAP's also come with a CPAP mode; some BiPAP and BiLevel machines Do NOT. By setting the IPAP and EPAP to the same pressure, a CPAP Mode is achieved, preventing the EPAP pressure from dropping.	Yes	Yes	Yes
Power Features
Direct Battery Operation Indicates which machines have a DC port in which you can use to connect a battery pack or a deep cycle marine battery with an optional DC cable. This is different from an integrated battery that works only with the machine it was designed for. (i.e. Everest CPAP Machine) see property Integrated Battery	Yes	Yes	Yes
Voltage Range Domestic Voltage is the voltage that is used with a standard wall outlet in the United States and ranges from 100-120 volts. International Voltage can range from 220v-240v AC.	100-240V AC	100-240V AC	100-240V AC
Optional DC Cable A 'Yes' answer indicates that the CPAP Machine has an optional DC cable that plugs directly into a DC port (see _Direct Battery Operation_). This allows you to use a DC power source, such as a battery or car cigarette lighter. Although some cables already come with battery terminal leads, some DC cables will need a separate part that connects the cigarette lighter adapter to another adapter with terminal leads.	Yes	Yes	Yes
Integrated Battery An integrated battery pack attaches to and functions seamlessly with the machine it is integrated with. It allows your CPAP to run on AC and fail over to the DC battery only if necessary.	No	No	No
Software Features
Advanced Software/Data Identifies which machines are data capable and have the ability to track your therapy progress over time. The machine captures key metrics like AHI (Apnea/Hypopnea Index), Leakage, and most pressure used. Depending on the machine, the data can be retrieved through an on Machine Screen Display (MSD), through Optional Software (OS), and/or through SmartCode (SC).	No	OS	No
Data Card This property marks the machines that have the ability to record performance data on a removable card. Some machines that are flagged as having software (seeOptional Software), do not have removable memory cards, rather instead, records information on-board and must use a download cable to retrieve the data from the machine.	Yes	No	Yes
Optional Software Software is an option on some CPAP machines. The software can give details on compliance and performance. The patient or physician downloads the data from the CPAP machine to determine how long a patient has used their machine each night and how well the machine is working to stop Apnea/Hypopnea events. This property shows the software package to use for machine that has the ability to transfer data to your computer and report Hours of Usage. See Advanced Software for a list of machines that can report AHI or Leakage.	EncoreViewer	Yes	No
Additional Features
Auto Altitude Adjustment Altitude Adjustment is defined as the machine's ability to compensate for changes in altitude. Compensation can either occur manually or automatically. Manual adjustments occur within the Setup Menu and must be set by the user. Automatic requires no user intervention.	No	Auto	Manual
Auto ON/OFF This feature turns the machines off and on when putting on or taking off the mask. When you put your mask on the machines senses you breathing and turns itself on. Take off the mask and the machine turns off.	Yes	No	Yes
Mask Off Alert This feature detects excessive mask leaks due to poor cushion seal or when a user stops therapy by removing a mask when in use. The alert can be in the form of an audible alarm (ALARM) or a text message on the unit's LCD display (LCD).	LCD; ALARM	No	LCD; ALARM
Spontaneous Spontaneous (S) mode tells the machine to start blowing at IPAP pressure with no specific interval set. The machine must wait and detect a break in the breathing cycle before reacting, switching from exhalation to inhalation. If a backup rate is needed, then the unit will need a time interval setting and will be marked 'Yes' on the Timed property.	No	No	No
Timed Timed (T) or Spontaneous Timed (ST) modes provide a customizable backup rate that forces the machine to switch from exhalation to inhalation. In ST Mode, the machine monitors the breathing cycle and switches from EPAP to IPAP once the backup time is met or whenever the break is detected through the sensors; whichever occurs first. The time aspect is only meant to act as a backup respiratory rate to the (S) function (see Spontaneous). This is used for patients with central sleep apnea, or those who need non-invasive mechanical ventilation.	No	No	No
Designed For Her These machines were designed with a woman's lifestyle in mind.	No	No	No
Customer Reviews
	5 4 3 2 1   0 Reviews	5 4 3 2 1   109 Reviews	5 4 3 2 1   40 Reviews

• 8 am to 10 pm CST Toll Free Phone and Email Support
• 24 hour access to our CPAPtalk.com Support Forum
• Learning Center for information on sleep apnea and cpap equipment
• Consumer Purchasing Trends Reports
• Product Evaluation Results from our Product Challenges
• Warranty Services for all items purchased through CPAP.com
• Insurance Compliant Invoices
• Free Prescription Request System

• A valid prescription is required for the purchase of this product.
• Philips Respironics products are for sale only to patients within the U.S. and not to other third parties or businesses.
• All services provided by CPAP.com, including advertisement, ordering, sale, delivery, instruction, and setup of the products are performed solely by CPAP.com and independently of the manufacturer.

Important Tips

CPAP Power Options

CPAP Video & FAQ

Videos

Frequently Asked Questions (FAQs)

What does CPAP therapy do?

CPAP therapy provides a constant airflow which holds the airway open so that uninterrupted breathing is maintained during sleep. It is traditionally provided through a nasal mask that seals around the nose to maintain the pressure level.

Which CPAP masks work on which machines?

All CPAP masks work with all machines.

How do I choose the machine that is right for me?

We provide our customers with many tools to make informed decisions about their machine purchases. Options include:

• Calling a CPAP Expert Toll Free. 1-800-356-5221.
  
  
• Comparison Charts. These charts compare available machines, feature by feature. If you don't know the meaning of a feature, click on the question mark for a definition. Click on the image or name of the product for more detailed product information, pictures and resources.
  
  CPAP Comparison Chart
  
  APAP Comparison Chart
  
  BiPAP Comparison Chart
  
  
• Help Me Choose Guide. We created a guide to help you select the right machine according to your preferences. The guide asks you a series of questions regarding your preferences and your prescription. Based on your answers we provide you with a comparison chart of the machine that meet your criteria. Get started here:
  
  Help Me Choose - Machine
  
  
• Browse Our Machine Product Categories. These categories show each machine our company offers, ranked by popularity. Popularity is determined by a mix of sales data and our in house opinion of the quality of the machine based on our experience and customer feedback. The best products float to the top of our categories.
  
  CPAP Machine Category
  
  APAP (Auto Adjusting) Machine Category
  
  BiPAP (Two Pressure) Machine Category

How can I compare different machines?

We work very hard to provide many different ways for our customers to compare products. Here are the machine product guides we have created and maintain:

• CPAP Machine Comparison Guide. This guide stacks up every CPAP machine we sell, feature by feature. If you don't know the meaning of a feature, click the question mark for a definition. The links below will take you to the most popular CPAPs, or all CPAP machines we sell.
  
  Compare Most Popular CPAP Machines
  
  Compare All CPAP Machines
  
  
• Auto Adjusting Machine (APAP) Comparison Guide. This guide stacks up every APAP machine we sell, feature by feature. If you don't know the meaning of a feature, click the question mark for a definition. The links below will take you to the most popular APAPs, or all APAP machines we sell.
  
  Compare Most Popular APAP Machines
  
  Compare All APAP Machines
  
  
• BiPAP, VPAP and BiLevel Comparison Guide. This guide stacks up every BiPAP machine we sell, feature by feature. If you don't know the meaning of a feature, click the question mark for a definition. The links below will take you to the most popular BiPAPs, or all BiPAP machines we sell.
  
  Compare Most Popular BiPAP Machines
  
  Compare All BiPAP Machines

What comes with my machine?

Machines come with a six foot hose, power cord, at least one filter, and manuals. Most manufacturers include a carrying case which is designed specifically for their equipment. CPAP / BiPAP / APAP machines do not come with a delivery system or mask. CPAP Masks must be purchased separately.

To see the list of what specifically comes with each machine, you can browse for a machine. Then on the product page, click the "Specs" tab to see a full list of what comes with the machine.

Do all CPAPs use filters?

Yes, all CPAPs use at least one filter that is usually a type of foam material and washable. Some CPAPs offer finer filtration with the addition of a disposable paper filter.

Cleaning and changing filters is the only maintenance required for a CPAP machine.

The filters are located at the back of the machine at the air intake. The image below shows the black foam filter at the back of the Everest 3 CPAP Machine.

Are prescriptions required for mask, machine and/or humidifier purchases?

Yes. Federal law requires we have a valid prescription on file before we ship your mask, machine and/or humidifier.

We provide many easy ways to get your prescription:

• We can request your prescription for you! When you checkout, just let us know you would like us to request your prescription, or you can log into your account to have us request your prescription.
• Fax your prescription to our Toll Free fax number: 1-866-353-2727, or our international fax number: 713-541-7370
• Email your prescription to cpap@cpap.com
• Upload your prescription in your account, under the prescriptions section

What is ramp?

The ramp button on a machine is a feature that allows for a gradual pressure build-up to your prescribed pressure. The feature is enjoyed by those with high pressures because they ease up to their pressure.

What is exhalation relief?

Exhalation relief is a comfort feature offered by two manufactures which reduces the air flow at the time of exhalation making the breathing process more natural.

• Respironics = C-Flex, C-Flex+, A-Flex and Bi-Flex
• Resmed = EPR (Expiratory Pressure Relief)

What is C-Flex?

C-Flex is a pressure relief feature that makes breathing back against CPAP pressure easier to do by reducing the pressure at the beginning of exhalation and returning to therapeutic pressure just before inhalation. Independent studies conducted by leading universities indicate that patient comfort, and therefore, patient CPAP compliance, is higher with machines that use C-Flex. C-Flex is a technology invented by Respironics, is proprietary, and is not available on other brands of CPAP Machines.

C-Flex Easy Breathing Technology Visual Graph

C-Flex vs. Traditional CPAP: Brown University Study

cpaptalk.com Interview, C-Flex in the Remstar Pro and Remstar Auto

What is the difference between Bi-Flex and C-flex?

C-Flex only works at the start of an exhale. Bi-Flex works during the transition from exhalation to inhalation, the transition from inhalation to exhalation and during exhalation.

What maintenance is required on machines?

The only care a CPAP or BiPAP machine requires is to clean or change the filters at the air intake. This keeps the internal parts from accumulating dust. Fine, paper filters should be changed out every 30 days, or when they appear soiled. Foam, washable filters should be rinsed with clear running water once a week, allowed to air dry, and reinserted.

There are some other suggested actions to care for your machine:

• Keep the area around your machine clean. Remove any dust from around the machine to improve the air quality delivered to your machine and you.
• Keep the air intake of the machine unblocked. Curtains, bedding, and papers can easily block the air intake of your machine, reducing the airflow.
• If a humidifier is used do not pick up the machine with the humidifier attached. With most machines it is easy to spill water from the humidifier chamber into the machine causing damage. Manufacturer warranties are voided by water damage to the machine. To avoid this, remove the chamber from the humidifier and then remove the humidifier from the machine rather than transporting them together.
• If a humidifier is used you should empty the water from the chamber every morning. Accidents happen. If a family pet or family member moves the machine and humidifier with water in the chamber it is more likely that water could be spilled into your machine. Water damage to a machine voids the manufacturer warranty.

What Data Capable Machines are available?

CPAP machines which record full data (like AHI and leak info):

• Philips Respironics M Series Pro C-Flex Machine
• Philips Respironics PR System One REMstar Pro CPAP Machine with C-Flex+
• ResMed S8 Elite II CPAP Machine
• Covidien/Puritan Bennett Sandman Info HC CPAP Machine with Built In Heated Humidifier (not to be confused with the model named "Intro.")
• Fisher & Paykel SleepStyle 244 CPAP Machine with Built in Heated Humidifier

• Philips Respironics M Series Auto CPAP Machine with A-Flex
• Philips Respironics M Series Auto CPAP Machine with C-Flex
• Philips Respironics PR System One REMstar Auto CPAP Machine with A-Flex
• ResMed S8 Autoset II CPAP Machine
• Covidien/Puritan Bennett Sandman Auto HC CPAP Machine with Built In Heated Humidifier
• DeVilbiss IntelliPAP AutoAdjust Travel CPAP Machine
• Fisher & Paykel SleepStyle 254 Auto CPAP Machine with Built In Heated Humidifier

• Philips Respironics M Series BiPAP Auto with Bi-Flex
• Philips Respironics BiPAP AVAPS Machine
• Philips Respironics BiPAP ST New Gray Model with Smart Card
• Philips Respironics BiPAP Auto SV
• Philips Respironics PR System One REMstar BiPAP Pro with Bi-Flex
• Philips Respironics PR System One REMstar BiPAP Auto with Bi-Flex
• ResMed S8 VPAP Auto 25 BiLevel Machine
• ResMed S8 VPAP ST BiLevel Machine
• DeVilbiss IntelliPAP BiLevel Machine with SmartCode
• Covidien/Puritan Bennett Sandman Duo BiLevel CPAP Machine with Built In Heated Humidifier
• Covidien/Puritan Bennett Sandman Duo ST BiLevel CPAP Machine with Built In Heated Humidifier

How do I use a battery to operate my CPAP?

First you need to determine if your machine is configured to operate on DC power and has a DC power outlet. If your machine does have a DC power outlet and you want to run your marine battery, then you will need the correct DC cable for your machine and an adapter cable that fits over the cigarette lighter plug and ends in alligator clips.

CPAP.com sells complete battery kits with everything you need for your machine including the right cables for your machine and the battery. You can find the right battery kit for your machine here.

If your machine does not have a DC power outlet, then you will also need an inverter to be able to run your machine on battery power.

If you have questions about the specific power needs of your machine, review the "Power" tab on your machine's product page, or give us a call at 1-800-356-5221.

What are the CPAP, BiPAP and Sleep Apnea related billing codes?

• EO601 RR is CPAP Rental
• E0601 NU is CPAP Purchase
• A7034 is CPAP Mask
• A7032 is CPAP Nasal mask cushion
• A7033 is CPAP Nasal pillows
• A7030 is CPAP Full face mask
• A7031 is CPAP Full face mask cushion
• A7044 is CPAP Oral interface
• A7027 is CPAP Hybrid mask
• A7028 is CPAP Hybrid mask cushion
• A7029 is CPAP Hybrid mask nasal pillow
• A7046 is CPAP Humidifier chamber
• A7037 is CPAP Tubing, long and short hoses
• A4604 is CPAP Heated tubing
• A7038 is CPAP Disposable filter
• A7039 is CPAP Gross particle (foam) filter
• A7035 is CPAP Headgear
• A7036 is CPAP Chinstrap
• E0561 NU is CPAP Passover humidifier
• E0562 NU is CPAP Heated humidifier
• E0470 RR is BiPAP Rental
• E0470 NU is BiPAP Purchase
• E0471 RR is BiPAP-ST Rental
• E0471 NU is BiPAP-ST Purchase

What does a CPAP prescription need to say?

• Contains one of the following words or phrases "CPAP" or "Continuous Positive Airway Pressure"
• Contains your physician's contact information
• Contains your physician's signature
• Contains the patient's full name
• Contains your specific pressure.
  • Example: 9 CM/H2O
  • Example: 9
  • Example: 14 CM/H2O
  • Example: 14

What does CPAP software do?

CPAP software allows the downloading of information from certain CPAP machines. Information on breathing, pressure levels delivered, apneas, etc. is available to help determine the effectiveness of CPAP therapy. Software is not required to operate a CPAP machine. CPAP Software also provides more data than obtained through the on screen display or SmartCode. The CPAP Software also allows you and your doctor to drill into any night of data recorded and view the data on an hour by hour basis.

Some CPAP manufacturer maintains a proprietary software package that is only compatible with their machines.

Here is a list of each manufacturer and the name of its related full data software:

• Philips Respironics: EncorePro - sold for Sleep Professionals
• Philips Respironics: EncoreViewer 1.0 - sold for Patient Use
• Puritan Bennett (Legacy 420 Series): SilverLining 3.10 - sold for both
• Covidien: Sandman Series Therapy Software 1.2 - sold for both
• Resmed: ResScan 3.3 and ResScan 3.7 - sold for Sleep Professionals
• DeVilbiss: SmartLink Therapy Management Software - sold for both
• Fisher & Paykel: Performance Maximizer - sold for both

• AEIOMed: DataRest Compliance Software Kit - sold for both
• Fisher & Paykel: Compliance Maximizer - sold for both

What types of Software are available?

There are two types of software available: Compliance software, and Advanced software.

Compliance software provides data such as patient hours, total machine operating hours, your pressure setting, and pressure relief information. Advance software includes compliance data and provides more detail such as AHI (Apnea/Hypopnea Index), Leakage, most pressure used, and a detailed usage histogram.

Compliance software is available with some standard CPAP machines. Advanced software is available with most top of the line CPAP machines, APAPs, and Bi-level machines as well.

How do I interpret my data?

Software data can be interpreted by your physician or clinician. There are also many websites and search engines available to help you research the sleep apnea related terms which will provide you more knowledge in managing your own cpap therapy. CPAPtalk.com. our free Sleep Apnea forum is a great resource for CPAP users who want to understand their condition and take control over their health.

What is CPAP therapy?

CPAP stands for Continuous Positive Airway Pressure. CPAP therapy is the most recommended and the most effective treatment for Obstructive Sleep Apnea.

A CPAP machine provides air at a constant prescribed pressure through a tube and out of a CPAP mask to a person with Obstructive Sleep Apnea. CPAP therapy provides a constant airflow which holds the airway open so that uninterrupted breathing is maintained during sleep. This eliminates sleep apnea events and allows the patient to get a restful sleep.

The pressure of the air is determined during your sleep study and your doctor will prescribe you a CPAP machine at that pressure.

CPAP therapy is traditionally provided through a nasal mask that seals around the nose. However, more innovative and comfortable options are available and advances in the delivery of CPAP therapy are continually occurring.

For instance: CPAPs with that boast FLEX or EPS technology will offer you exhalation relief. APAP, BiPAP and BiLevel machines offer various levels of pressure throughout the night and exhalation relief.