Receivers allow you to monitor up to 8 different STI wireless alert devices at a single, convenient location. Supervised for low battery and signal reception, they have an audible chime tone or 12 VDC output for siren. Devices can be latching or momentary by zone. STI offers multiple wireless products designed to alert you of several different conditions (such as: an open garage door, mail delivered, a car in the driveway, open exit door, removed fire extinguisher or activated push button, etc.).