Carbon Monoxide Alarm, Detection Method Electrochemical, No Interconnection Capability, Power Source 120VAC, 9V, Audible Alert 85dB @ 10 ft., Horn, Visual Alert Red LEDHeight 6-1/4 In., Depth 1-3/4 In., Width 3-3/4 In., Digital Readout Yes, Battery Backup Yes, Features Direct Plug In, Monitors CO Levels from 30 to 999 ppm, Samples Air Every 2.5 Minutes, Peak Level Memory, Mounting Options Direct Plug, Wall Mount or Tabletop Stand, Hush Button No, Locking Pin No Carbon Monoxide Alarms85dB horn sounds when sensor detects high levels of CO. Visual LED indicator alerts user when alarm needs replacement. Operating temp.: 40 to 100 F.IAS6-96 Certified and UL 2034 Listed, except 5U747 and 4XP95 are IAS6-96 Certified OnlyPlug-In CO Alarms6AJW6 has tamper-resist feature that sounds a constant alarm if unit is unplugged or comes loose from wall outlet. 5U747 and 4XP95 include an extension cord for table or shelf mounting. 4XP95 includes a rechargeable battery.