Widely used for room, hall, kitchen, party, no smoking place, Hotel, Factory...etc. Alarm mode: while smoke density reach the limited, it gives off alarm warning as well as sending wireless signal to alarm panel, High sensitivity, interconnect up to alarm. Unique "battery missing" lockout. Customized. Specification: 1.Battery operated: DC 9V. 2.Rechargeable li-ion battery 10 year 9 DC battery. 3.Photoelectric sensor. 4.Red LED indicate alarm. Green LED mains indicator light to confirm battery power supply 5.Test button, Low battery alarm 6.Relay contacts-volt free with Normally open and Normally closed options and rated to 24 volts/1 amp resistive. 7.Alarm supplied with" connector plug" for easy of installation ,built in sounder to give a minimum sound output of 85 dB at 3 m senses smoke using the light scatter principle-quick response to visible smouldering smoke, test button simulates smoke- use to check performance at least monthly, option current <10uA, alarm current<30 UA. 8. Standard compatiabl:ISO 12239, EN 54-7, BS 5446-1, EN 50134-2, I-ETS 300220