As8900 4 in 1 muilt gas monitor introduction The as8900 multi-gas monitor is a portable and handheld instrument that is capable to use continuously and simultaneously monitoring 4 gases: oxygen, combustile gas, carbon monoxide and hydrogen sulfide. Every gas readings all shows in one lcd display. The unit also provide user to configure high and low alarm as well as twa and stel alarms. The unit will be audio and visual alarm once the alarm condition is exceeded. As8900 4 in 1 muilt gas monitor specifications * range: Oxygen (o2): 0~30% Combustile (lel): 0~100% lel Carbon monoxide (co): 0~999 ppm Hyrogen sulfide (h2s): 0~500 ppm * operating temperature: -10~ 50'c(except lel is 0 ~40'c) * operating humidity: 15~95 % rh, typical * size: 120.20 x 64.50 x 38.30mm * weight: 200g