The Kidde p12040CA us a 120V AC, wire-in smoke alarm with 9V battery backup that can function as a stand alone unit or interconnect with up to 24 Kiddle devices (of which 18 can be initiating).  The Kidde p12040CA provides continuous protection against smoke and fire hazards, even during power outages.

• Photoelectric technology - may detect visible fire particles (associated with slow smouldering fires) sooner than ionization alarms
• 120V interconnectable - will interconnect with up to 24 other devices
• 9V battery backup - provides continuous protection even during power outages
• Multi-function one button design 
• Hush feature - temporarily silences nuisance alarms
• Test feature - simultaneously tests the units electronics and verifies alarm operation
• Tamper resist feature - tamper resist locking pin deters from tampering or theft
• cUL listed
• 10 year warranty