The GasWatch 2 is a single-gas portable monitor that detects O2, CO, or H2S. It can be worn comfortably either on the wrist, belt, hard-hat or clipped to protective wear. The built in vibrator, audible, and visual alarms immediately alerts the user of a dangerous gas condition. Advanced capabilities include distinctive audible and visual alarms, a digital readout with manual backlight even in alarm conditions, as well as PEAK, TWA, and STEL display readings. The GasWatch 2 operates for over 3,000 hours on one battery (about 1 year normal use). It even tells the time.