* This small magnetic reed switch senses when a door or window opens and can alert you with either an alarm or chime.
* This makes it suitable for both security purposes or for notifying you when customers arrive at your business.
* Features 4 modes of operation; Intruder Alarm, Entry Doorbell, Open Alarm and Door/Window Open Reminder.
* Simple two piece design attaches with double sided tape.
* Requires 2 x AAA batteries