STI-6402 Exit Stopper Door AlarmThe highly effective Exit Stopper can serve as an inexpensive security device and help stop theft by alerting you to any unauthorized exits or entries through emergency exit doors. If the protected door is opened, the electronic Exit Stopper emits an ear piercing alarm for 30 seconds, 3 minutes or continuously (as preset by the user). A key operated override will silence the alarm and allow authorized exits. The unit can be set for a 15 second delay