RCM4 Carbon Monoxide Smart Sensor is Pre-Calibrated at two levels for the best Accuracy. It comes packaged with a Certificate of Calibration

Features:

• Field-replaceable CO Sensor comes pre-calibrated & certified
• Easy to Install
• Advanced three-pin sensor measures 0 to 1000 ppm CO 
• Calibrated Sensor / Zero the SCM4 to ambient quickly with the ZERO button
• Lasts approximately two years [useage pending]