The 433MHz Wireless Universal Transmitter can send an instant RF signal to your DSC 8 - 32 Zone Security System in the event that an unwelcome intruder attempts to enter your home. The security system receives wireless signals through the 433MHz Spread Spectrum Wireless Receiver or LCD Keypad with built-in 433MHz Wireless Receiver, which is required for any wireless transmission and is sold separately. Runs on an included 3V Battery (CR123A). The Professional 8 - 32 Zone Security System with X10 & Intercom consists of the Power 8 Zone Security Panel and Cabinet, the Power 8-32-Zone Alphanumeric LCD Keypad, a 12V Backup Battery, a 16VAC 40VA Power Supply, and the 30-Watt Weatherproof Siren, all required and sold separately. Door/window contacts, PIR motion sensors, and additional accessories are also sold separately. Ideal for door and windows, the 433MHz Wireless Universal Transmitter can be used directly on the frame with included magnet mounted on the door or sash. Terminals are also included for an external switch.