The Wireless Transmitters category can be very confusing to some people if you don't learn a few bits of information first. A transmitter transmits to a receiver. A receiver connects to your TV, VCR, or other recording device. All transmitters and receivers require power or electricity. A wireless camera only eliminates a video wire between the camera and TV or recording device. Only wireless hidden cameras have the transmitter built into the object. Outdoor weatherproof type, indoor bullet, professional box, and infrared wireless cameras all utilize an external transmitter.