Smoke Alarm Type:AHS-2 1.Power supplied DC9V battery and back-up source 2.110V-240V AC mains power supply 3.Supply voltage DC12 to 30 volts 4. lithium 5year 9 volt batteries(Optional) 5.Interconnect up to alarms 6.Sensor type: Photoelectric sensor 7.Plastic box: Fire resistant material 8.Red LED mains indicator light to confirm mains power supply Green LED mains indicator light to confirm mains power supply 9.Unique" battery missing" lockout 10.Low battery alarm 11. test button simulates smoke-use to check performance at least monthly, 12.Relay contacts-volt free with Normally Open and Normally Closed options and rated to 24 volts /1amp resistive 13.High sensitivity 14.Alarm supplied with "connector plug" for ease of installation 15.Built in sounder to give a minimum sound output of 85db at 3m Senses smoke using the light scatter principle-quick response to visible smoldering smoke, option current ≤10μA, alarm current≤30mA 16.CE Approval, UL standard.