Designed for quick servicing—you can change the battery without removing the alarm from the ceiling. Convenient Hush® button to silence nuisance alarms. Includes ionization sensor, test button, low battery signal and flashing LED power light. Requires 9V battery (included). UL Listed. Manufacturer's limited five-year warranty. Maximum Height: N\A; Battery: 9V; Wall-Mountable: Yes;Universal Mounting Bracket: Yes.