The Triplett Model GSM130 Portable Carbon Monoxide Meter with user-adjustable CO alarm level has a range of 0ppm 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 30ppm, 35ppm, 40ppm, 45ppm, 50ppm, 70ppm, 100ppm and 200ppm. Additional features include automatic calibration in clean air (0ppm) or use 100ppm/500ppm standard gases, backlit dual LCD display and Auto power off. Includes 3 AAA batteries, wrist strap and pouch case. 1-year warranty.