The battery-operated Digital Carbon Monoxide Detector with Auto Zero Function from General Tools features an electrochemical CO sensor with three points of auto calibration: 0, 100 and 500 ppm. The meter has a backlit LCD display and simultaneously exhibits dual readings of the current CO level and maximum level since the meter was powered on (updating every second). Other features include automatic calibration to 0 ppm in fresh air and an audio alarm that can be set to sound whenever the CO level exceeds any of eight selectable levels to indicate a dangerous CO concentration. It has a measuring range of 0–1000 ppm and comes complete with a soft case, a wrist strap, three AAA batteries and an instruction manual. The detector is ideal for HVAC contractors, plant operators, automotive experts and other professionals.

California residents: see   Proposition 65 information

• Carbon monoxide (CO) range: 0–1000 ppm
• LCD dual digital display also shows ambient temperature
• Adjustable CO warning level
• Includes three AAA alkaline batteries, operation manual, wrist strap and carrying pouch
• Bright backlight
• Low battery indication
• Battery life is 250 hours with the backlight off and 35 hours with the backlight on