SRZ-CF25F3 Oxygen Sensor replaces Figaro Model KE-25F3 oxygen sensor. It is a galvanic type micro fuel cell and is specific to oxygen. Designed for O2 analysis in gas streams containing any level of CO2 gas; acidic electrolyte formulation used in the sensor makes it compatible with CO2 and other acid gases. It offers longer life without signal drift and minimizes periodic calibration requirement. AST brand sensors are designed, developed and manufactured in the USA.