Safety Technology International - STI 6400 Exit Stopper Multifunction Door Alarm. Helps prevent unauthorized exits or entries through emergency doors. If the protected door is opened, the electronic Exit Stopper (STI-6400) emits an ear piercing 105 dB warning horn, which will draw attention in a hurry. When activated, the alarm will continue for 30 seconds, three minutes or continuously (as preset by the user). A key operated override will silence the alarm and allow authorized exits. Another option is annunciator mode, in this mode it announces a doors opening with a set of 10 beeps and then resets. This highly visible “stop sign” design acts as a deterrent, completely self-contained and easy to install. May be mounted on top, right, left or next to almost any door. Exit Stopper is fitted with a long life 9-VDC alkaline battery. It is available in red or green for almost any type of door, mounting or installation. Has a 3 year guarantee against breakage of polycarbonate in normal use (one year on electro mechanical and electronic components). Safety Technology International, Inc. "We protect the things that protect you"