SRX-CT22A % Oxygen Sensor is specifically designed for measuring oxygen in automotive exhaust. SRX-CT22A replaces Teledyne R-22A, Part Number C44611-R22A, Envitec 00A101, AO2 CiTicel and IT Gambert A-01. Fast response – from air to less than 0.1% in under 30 seconds. This sensor is similar to R21A except mV output in air. SRX-CT22A % oxygen sensor is a galvanic type micro fuel cell specific to oxygen. Its proprietary electrolyte formulation ensures full utilization of Pb anode, thus providing longer life without signal drift and minimizing periodic calibration requirement. Sensor is designed, developed and manufactured in the USA