Also prevents occupants from using extinguishers for door stops and other inappropriate purposes. The stopper alarm by STI mounts to the wall with a standard screw. Once the cable is placed around the neck of an extinguisher, attempted removal will activate the 95db siren. A deactivation device is included to allow for routine maintenance. Requires a standard 9V battery. (Included) Measures 136mm in diameter and 50mm deep.