Respironics introduces "System One" through PR Series of CPAP machines. The PR 150 CPAP machine is the entry level system and uses the new System One technologies like Humidity Control with Dry Box and Resistance Control. The PR CPAP humidifier and water chamber design are breakthroughs for managing rain-out and water damage. System One Humidity Control technology analyzes ambient temperature and patient airflow to reach relative humidity at the mask. Choose from 5 levels of relative humidity. System One is the first humidifier in the industry which accounts for room humidity. Sensors inside and outside the CPAP machine closely monitor changes in humidity and prevents condensation from forming inside the tube. Dry Box technology is another breakthrough in reducing water damage to the CPAP. Several unique designs are incorporated into the humidifier to prevent water from exiting the chamber. To start, the air outlet port has been moved from the side of the humidifier onto the top. This centers the entire delivery; minimizing the total water displacement around the hole. The water chamber is outfitted with one-way valve, between the machine and the humidifier. Any water that manages to escape the chamber gets trapped within the Dry Box, which acts as a reservoir for any water ingress past the valve. System One and Dry Box Technology make it possible for the PR CPAP machines to be truly spill-free.