The MSA O2 Oxygen Sensor is designed for use with Altair 4X, 4XR, and 5X gas monitors. It is a high-quality, brand new unit manufactured by MSA in the United States. The XCell O2 sensor is specifically designed to detect oxygen levels, making it a reliable and essential component for monitoring and ensuring safe working environments in various industrial settings. With a unit quantity of 1, this oxygen sensor provides accurate and dependable measurements to help maintain air quality and safety standards.