Rain-out and water damage are large contributors to machine failures. The PR System One humidifier and water chamber are breakthroughs in delivering consistent humidity without compromising water management. System One and Dry Box Technology make it possible for the PR CPAP machines to be virtually spill-free. This humidifier can be tilted, shaken, or turned upside down without water leaking back into the device. Even with a chamber filled to the "Full" indicator line, this unit can be transported safely and reliably.