SRX-CA120 % Oxygen Sensor is for oxygen purity analysis. Its a drop-in replacement to Analytical Industries Model GPR-11-120 and GPR-11-120-OP oxygen sensor. This sensor is used in GPR-3100, GPR-3500MO and GPR1200MO analyzers. This sensor has a lower signal output in air but has similar characteristics as of SRX-CA32 thus making it suitable for measuring high levels of oxygen. At ambient temperature and pressure, in 100% oxygen, the expected sensor life is 24 moths. AST brand sensor are designed, developed and manufactured in the USA.