The Model 4000 ALERT ™ is a 12-volt, powerful 50-watt electronic siren that has three different functional siren sounds - WAIL, YELP, AIR HORN and P.A system. Built with state-of-the-electronics throughout to provide years of dependable service. The compact size of the siren controller makes mounting possible in vehicles that have little open space available in the dash area. The three emergency sounds and public address system have a full range of adjustable sound output, which is controlled by a simple turn of the rotary volume control. Select air horn or siren sounds by the simple press of a push button. The Model 4000 is great for volunteer fire personnel in states that permit use of sirens. Comes complete with a 100 RMS speaker, plug-in microphone, metal mounting bracket and mounting hardware. Instructions in English / Spanish