AST-75D oxygen sensor, a galvanic type micro fuel cell specific to oxygen, replaces AII Model AII-11-75D oxygen sensor used in Trimix-4001 analyzer. AST-75D oxygen sensor offers 60 months life in air at ambient temperature and pressure. 3-PIN Molex connector, M16x1 front end thread. Its innovative design with proprietary Pb anode structure provides with excellent stability and ensures full utilization of the anode without signal drift thus minimizing frequent periodic calibration requirement. AST brand sensors are designed, developed and manufactured in the USA.