Including 6 models, Exit Stopper alerts if any protected door is opened by emitting ear piercing alarm for 30 sec, 3 min, or continuously as preset by users. In annunciator mode, it announces door entry with set of 10 beeps. Model STI-6400 is original multifunction door alarm, Model STI-6402 is designed for double door installation, Model STI-6404 suits double door with remote horn, and Model STI-6406 allows for dual access control. Model STI-6403 has remote horn, and Model STI-6405 has always active feature.