Complex Sealing Assembly
Double silicone diaphragm in the middle of the assembly and the 2 mating outer components (polycarbonate).
Topical oxygen therapy
The check valve stops the flow of oxygen out of the bag if the patient disconnects from the oxygen source. The relief valve maintains the inflation pressure inside the bag so that the bag is inflated and maintains its optimal pressure setting. Combining these two functions into a single double diaphragm reduced the part count, eliminated separate springs and seals, and simplified assembly.