15 Watt wall mounted 2-Tone siren for indoor use. Make sure you are notified whenever an alarm is triggered with this Universal Power Group D1306 SP36ULB security siren. This powerful hard wired siren will be a great addition to any hard wired security system. Connect the appropriate wires to your hard wired security system, depending on which of the two tones you would like to hear. This tone will then be heard whenever the siren is triggered by an alarm, generated from the security system. The D1306 SP36ULB is intended for indoor applications, it is a good idea to locate the siren in an area in which the intruder will not be able to pin point (attic or crawl space). This will ensure that your siren is not damaged or disconnected by the intruder.