When you're only worried about hydrogen sulfide exposure, bulky monitors with multiple filters and functions just get in the way. That's why experienced workers depend on BW Clip Extreme H2S Monitor every single day: it keeps things simple. Indeed, it's hard to find a simpler H2S detector. You turn the Gas Alert on once, and it stays on for the for the entire span of its two year battery life. It can't be turned off, so you never have to worry about turning it off accidentally. You don't even have to calibrate it (though you can bump test the unit if you want). The monitor's simplicity is complemented by its portability. At 76 grams, the GasAlert is both light and compact, which encourages workers to strap the unit to their work clothes. That's important! After all, a gas sniffer only does you any good if you take it into the field! If you have any questions, please don't hesitate to give us a call at 800-829-9580, or visit us online at www.pksafety.com, and follow us @.