Features:*LCD display the carbon monoxide gas concentration from 000-999PPM.*Human voice prompt, when reach the given alarm level, the detector will alarm and voice prompt.*Adopting high reliable and stable electrochemical sensor,effectively detect the real-time CO gas and remind people.*Low current consumption, ultra-long standby time.*Silence your gas detector by immediately pressing the test button when non-emergency gas.*Low battery warning. The LCD screen show LB and voice prompt attention please,low battery warning.*Press the TEST/RESET button, can view the alarm levels.*When the detector is in fault,it will displaying ERR.