The Triplett Model GSM130 Portable Carbon Monoxide Meter with user-adjustable CO alarm level has a range of 0 to 999ppm and simultaneously displays current CO and Max CO levels. It can be used to check Carbon Monoxide (CO) levels in chimneys/flues, gas appliances (ovens, ranges, dryers), furnaces, internal combustion engines, portable generators, and all coal/wood/charcoal/oil/kerosene/propane/natural gas burning devices.  It features a 25ppm default alarm setting with user selectable settings of 30, 35, 40, 45, 50, 70, 100 and 200ppm. Additional features include automatic calibration in clean air (0ppm) or use 100/500ppm standard gases, backlit dual LCD display, and Auto power off. Includes (3) AAA batteries, wrist strap and pouch case. 1-year warranty.