120V AC/DC Smoke & Carbon Monoxide Alarm, Easy Installation/Maintenance, Include A Large Opening In The Mounting Bracket For Easy Access To Wiring, Key Hole Slots In The Mounting Bracket Eliminate The Need To Remove The Electrical Box Screws For Installation, A Battery Pull Tab Keeps The Battery Fresh Until The Home Is Occupied, Battery Installation & Removal Can Occur While The Unit Is Mounted To The Ceiling Or Wall Via The Side Load Battery Compartment, 2 Locking Features Are Provided To Prevent Battery Theft &/Or Theft Of The Unit, Connection To AC Power Is Made With A Quick Connect Wiring Harness, Installation Is Quick, Easy & Cost Effective.