The Microwave Transmitter utilizes a Schottky diode oscillator module feeding a tuned waveguide and horn to give a directional microwave beam. The beam is modulated with a variable frequency audio signal which can be adjusted by the control on the top panel. Power is from a mains plug-top unit (supplied).Additional parts available:Microwave Receiver Unit: B8R09404Microwave Probe Receiver: B8R09450Microwave Accessories: B8J73480Full Microwave Kit with Accessories: PP053304