Note: This item is shipped from China(Hong Kong); Delievey time: 10-15 business days. 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. Alarm memory feature: If the unit ever alarms, pressing the button, green LED will flashes once every second for one minute and the peak alarm level will be indicated on the LCD. 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. Green LED Flashes every 30 seconds to indicate the unit is operating properly. The green LED will also flash before CO reading is taken and when any button is pressed. Red LED When a dangerous level of carbon monoxide is detected the red LED will pulse and a loud alarm pattern will sound. Specifications Power Supply 3 pcs 1.5V AA size batteries (not included) Sensitivity & Time 50ppm, alarms within 60~90 minutes 100ppm, alarm within 10~40 minutes 300ppm, alarms within 3minutes Sensitivity Range £¼2.5m Standby Current <50uA Alarm Current <50mA Operation Ambient Condition 5~40C, 20~90%R.H Package Content 1x Carbon Monoxide Alarm 2x Screws 1x English User Manual