The First Alert CO605 carbon monoxide alarm uses an electrochemical sensor the most accurate technology available. The permanent sensor lasts up to 5 years. This carbon monoxide alarm plugs into any standard electrical socket and monitors your space for elevated carbon monoxide levels. The test/silence button silences the alarm and allows you to test its functionality. The unit monitors and re alarms if carbon monoxide level persist sounding a loud 85 decibel horn. This CO detector also features a battery backup that allows for continuous monitoring, even in the event of a power failure. The simple, user friendly design makes this CO detector easy to setup and operate, and it features an end-of-life warning that lets you know when it is time to replace the unit. Plug-in CO alarm works with any standard outlet and has a battery backup for continuous monitoring during a power failure Advanced electrochemical sensor detects carbon monoxide levels no matter where the detector is installed A loud 85-decibel alarm sounds when CO levels reach dangerous levels CO alarms should be placed on every level and in every bedroom of the home 7-Year limited warranty Tested to meet UL standards Color/Finish Family: White Series Name: CO605 Height (Inches): 5 Length (Inches): 3.4 Width (Inches): 1.38 10-Year Battery: No Battery Back-Up: Yes Battery Included: Yes Battery Type: 9-volt Carbon Monoxide Detector: Yes Display Type: Analog Hub Required: No Interconnection: No Natural Gas Detector: No Package Contents: 2 Alarm, 2 9 volt battery, manual Package Quantity: 2 Peak Level History: No Power Source: Plug-in Propane Detector: No Sealed Battery: No Voice Alert: No Voice Assistant: No Voltage (Volts): 120 Warranty: 7-year limited App Compatibility: No Bluetooth Compatibility: No Smart Compatible: No Wi-Fi Compatibility: No Works with Apple HomeKit: No Works with iOS: No CA Residents: Prop 65 Warning(s): No Safety Listing: UL safety listing UNSPSC: 46191500