Gasboard-8500V series ultrasonic oxygen sensors are an economical gas sensors used to detect oxygen concentration in binary gases. By adopting ultrasonic detecting technology and principle of TOF (time of flight) measurement, these sensors are very stable, high accuracy, maintenance-free, no drift, no need routine calibration and no-consuming parts, can continuous monitor with long life span. Gasboard 8500V series sensors are small size and easy to be integrated to medical ventilator and other equipment.