The MSA 261 is a portable indicator & alarm for monitoring oxygen (0-25%) and combustible gas (0-100% LEL). An internal sampling pump allows the sample to be drawn to the instrument from a remote location prior to human entry. Operates for 8 to 10 hours on a full charge. The large display is easy to read and has a momentary switch for back lighting. Low battery alarm and visual alarm indicators. UL approved for hazardous locations. Includes: Instrument, sampling probe, charger.