The WIR RX18 is a under-the-chin style two-channel infrared receiver designed for use with a transmitter operating on 2.3 or 2.8 MHz or stereo. This easy-to-operate, stethoscope-style receiver is ideal for listening applications where optimal sound quality is essential. Provides a range of up to 3,063 square feet (285 square meters) in single-channel mode when used with a WILLIAMSAV WIR TX925 or WIR TX90 infrared system. Lightweight, one-piece design is comfortable and easy-to-clean. An on/off control is built into the arms of the unit, saving on battery life. BAT AP11A battery is included. Use with optional CHG 518 charger.