he MSA ALTAIR is a reliable high-performance single-gas detector with sensor options of CO or O2 and provides two years or 1080 alarm minutes of service life under warranty with no maintenance. This instrument will not deactivate after two years of operation but will continue to perform as long as battery capacity allows. No calibration, sensor change or battery change is needed.Patented, MSA Button toxic gas sensors are fitted to both the CO and H2S ALTAIR, while the O2 version accommodates a fast responding 20 series sensor. ALTAIR and can be worn securely anywhere. This rugged clip design keeps the unit attached during even the roughest use.