Features: 1. Carbon monoxide announciator, electrochemical sensors, combined with the living environment of people, through scientific design, the detection signal is very sensitive and accurate; 2. The carbon monoxide detector using high-performance microcontroller, it can detect low to several PPM concentrations of carbon monoxide; 3. Reset, two key test is simple and convenient, you can restart or to test environment of carbon monoxide concentration at any time; 4. Just as the size of a hand, very convenient to test at different places; 5. Adopt the ultra-low power consumption, use 3 pieces of AA batteries, the battery can be used more than 2 years in normal working environment . 6. Powered By: 3 x AA Batteries (Not included). Package: 1 x Carbon Monoxide Detector Alarm( not included battery) 2 x Screws 1 x Englsih User Manual

The alarm sound pattern is four short alarm beeps.The red LED will flash whilte in alarm mode, .One" chirp" every 30 seconds is an indication that the battery is low ( need replacement) ( gree LED still flashes once every 30 seconds) or the unit is malfunctioning ( green LED is out).