5 Inch Diameter, Smoke Alarm Price For: Each Alarm Type: Smoke Alarm Power Source: Battery Sensor Type: Ionization Mount Type: Wall or Ceiling Interconnectable: Yes Decibel Rating (dB): 85.00 Batteries Included: Yes Warranty (Years): 10 Tamper Resistant: Yes Low Battery Warning: Yes Indicating Light: Yes Battery Size/Type: 9V Diameter (Decimal Inch): 5.0000 Projection (Decimal Inch): 1.5000