120-volt AC wired-in smoke and fire alarm with 9-volt battery backup. Super heavy-duty battery included. Quick Draw® battery drawer. Loud 85 dB alarm. Test/silence button. Microprocessor virtually eliminates nuisance alarms. Power and alarm LED’s. Product end-of-service life warning. 2 tamper resistant locking features. Interconnectable up to 24 compatible devices. Listed to UL217 Standard.