A wireless system consists of two main components: a transmitter, and a receiver. The transmitter handles the conversion of the audio signal into a radio signal and broadcasts it as a radio wave via an antenna. The antenna may stick out from the bottom of the transmitter or it may be concealed inside. The strength of the radio signal is limited by government regulations. The distance that the signal can effectively travel ranges from 100 feet to over 1,000 feet, depending on conditions and quality of signal. Transmitters are available in two basic types. One type, called a “body-pack” or “belt-pack” transmitter, is a small box about the same size as a pack of playing cards (or smaller in some cases). The transmitter clips to the user’s belt or may be worn on the body. For instrument applications, a body-pack transmitter is often clipped to a guitar strap or attached directly to an instrument such as a trumpet or saxophone. In the case of a handheld wireless microphone, the transmitter is built into the handle of the microphone, resulting in a wireless mic that is only slightly larger than a standard wired microphone. Usually, a variety of microphone elements or “heads” are available for handheld wireless microphones. All wireless transmitters require a battery (usually a 9-volt alkaline type) to operate.