AST-22D diving oxygen sensor replaces Teledyne R-22D and R-22S % oxygen sensors. AST-22D also replaces AII Model PSR-11-39-MD, PSR-11-39-rEvo,  City Technology CT-1 and CT-12 diving oxygen sensors. This sensor fits in these rebreathers; KISS, Interspace Megalodon, Oxy Spy, Oxy2, Optima, Hollis Prism and Poseidon Rebreathers. Supper activated anode material along with proprietary electrolyte formulation ensures full utilization of Pb anode. This combination provides much longer sensor life without significant signal drift thus minimizing periodic calibration requirement. Sensor is designed, developed and manufactured in the USA