Stopper II protective cover has helped stop false fire alarms around the world for over 40 years, without restricting legitimate alarms. Cover mounts directly to the wall over an existing pull station. When lifted to gain access to the actual alarm, it sounds a self-contained 95 or 105 dB piercing warning horn. Immediate attention is drawn to the area and the prankster will either run or be caught. Surface mount cover consists of a clear, super tough polycarbonate shield and spacer that fits over manual pull stations. Ideal for public buildings. Three year guarantee against breakage of polycarbonate in normal use (one year on electro mechanical and electronic components). UL/cUL Listed, ADA Compliant, FM Approved.