Highly effective, alarm alerts you to any unauthorized exits/entries through emergency exits with double doors. Serves as an inexpensive security device and helps stop theft as well. If the protected door is opened, the electronic Exit Stopper emits an ear piercing alarm for 30 seconds, three minutes or continuously as preset by the user. A key operated override will silence the alarm and allow authorized exits. Exit Stopper is fitted with a long life 9-VCD alkaline battery. It is available in red or green for almost any type of door, mounting or installation.