433MHZ Glass Break Sensor/Transmitter - Self contained 4 3/4" x 3 1/4" x 1 1/4" sensor uses sophisticated IC circuitry to detect the sound of breaking glass. It processes this noise signal and then transmits a 433MHZ signal to activate your receiver (such as our C6849 433Mhz Keychain Remote control System Kit). Requires no wires and uses one 9V battery (not included). Beige case. Fully assembled.