The COA1 is a Carbon Monoxide adapter that is iPhone or Android phone compatible. It also works with UEi clamp head adapter (CHA1). It features a Range of: 0-999 ppm and an Accuracy of: ±3% of reading +1 ppm and a Resolution of 1 ppm.. The phone app has a visual indicator: Off 0-1 ppm; GREEN 2-9 ppm; AMBER 10-34 ppm; RED 35 ppm or higher.
Warning: this product contains a chemical known to the State of California to cause cancer. P65Warnings.ca.gov