9v, battery operated, smoke alarm, with silence/mute button, mutes unnecessary alarms immediately, also tests alarm function with same button, ez access battery door, no need to remove alarm from ceiling to change battery, optional theft prevention lock when activated, batteries &/or alarm cannot be removed without proper tools, ionization smoke sensor, optimal smoke detection from flaming fires, loud 85 decibel alarm, uses 9v battery, included, meets ul217 standard, 10 year limited warranty, note: please check your local building code requirements before installing this product to determine compliance with applicable standards.