Carbon Monoxide Detector Adapter [custom1] Detect CO to 1 ppm Reads up to 999 ppm CO Use with compatible iPhone or Android smart phones Free App displays 3 Visual Danger levels App allows logging and emailing capabilities Compatible with select UEi Clamp meters Clamp Meter use requires Clamp Head Adapter CHA1 (not included) CHA1 available with a COA1 online product registration [/custom1]