Brand New and High Quality,LCD Displayer with a Blue Ground Light.Loud 85 decibel alarm,Permanent Carbon Monoxide Sensor,The Alarm Sound Pattern is Three Short Alarm Beeps. The Red LED Will Flash While in the Alarm Mode. * One chirp every 30 seconds in an indication that the battery is low (need replacement) (green LED still flashes once every 30 seconds). * Test/Reset button to test the unit electronics and verifies proper unit operation and reset the unit during CO alarm. * Green and red LED lights that indicate normal operation and alarm status. The unit will sound chirp and red LED flashes once as power up. * Red LED:When a dangerous level of carbon monoxide is detected the red LED will pulse and a loud alarm pattern will sound.