Acoustic Research AW721 900 MHz Wireless Stereo Headphones (Discontinued by Manufacturer) Pair of wireless stereo headphones with transmitter for indoor or outdoor use 900 MHz frequency transmits at distances of up to 300 feet RCA-type audio inputs connect to TVs, DVD players, AV receivers, MP3 players, and more RF noise reduction system reduces interference for high-quality sound Transmitter doubles as charging base; self-adjusting headband and cushioned ear cups