Stopper II consists of a clear, tamper proof, super tough polycarbonate shield and frame that fits over manual pull stations. When lifted to gain access to the actual alarm, it sounds a piercing self-contained 95 dB or 105 dB warning horn (at one foot). Immediate attention is drawn to the area and a prankster will either run or be caught. The cover is connected to the frame by a cable. When the cover is lifted, it drops off of the frame and a horn will sound (models with horn). Horn will sound until the cover is snapped back onto the frame or for the life of the battery. Also known as -SAFETY TECHNOLOGY STI 1200 STOPPER II COVER WITHOUT HORN RED-SAFETY TECHNOLOGY INTERNATIONAL STI1200 Pull Station Guard,Polycarb,Surface