KIDDE 21007309 Carbon Monoxide Alarm, Electrochemical. More details: Carbon Monoxide Alarm, Detection Method Electrochemical, No Interconnection Capability, Power Source 120VAC, 9V, Audible Alert 85dB @ 10 ft., Chirp, Visual Alert Red LED, Height 3 In., Depth 1-1/2 In., Width 5-1/2 In., Digital Readout Yes, Battery Backup Yes, Features Tamper Resistant, Plug-In, End-Of-Life Alarm, Hush Button No, Locking Pin Yes, Operating Temp. 40 Degrees to 100 Degrees F, Standards UL2034, Manufacturers Warranty Length 7 Year Limited