Horns & Sirens by Seco-Larm. They can serve as a regular sirens, but also features an audio input that can be used to playback audio or broadcast messages The SH-816S-SQ series also includes a strobe light with a Blue lens and can be surface installed or to a standard single gang, double gang or C-type back box Key Features 120dB Warble-tone siren 25W Speaker Bright Blue xenon tube strobe light Audio input for broadcasting messages or audio playback 9 to 15 VDC operating voltage, Works on external power source Low current draw Built.