Safeguard your family members and co-workers as well as your property with this reliable alarm. Its front-loading battery door means you can change batteries without removing alarm from mounting bracket. Door won't close unless battery is properly installed. Equipped with a tamper-resistant locking feature to alleviate concerns about theft and tampering. Includes feature that allows you to silences nuisance alarms. Adjustable mounting bracket for fast installation and perfect alignment. Requires 9V battery (incl.). Test/reset button tests all functions including battery.