Sony 150 feet Expanded Long Range RF Wireless Noise Reducing Dynamic Stereo Headphones with Volume Control, Mute Switch & Adjustable Comfortable Wide Headband for all VIZO M320SL, M3D470KDE, M3D550KDE, M3D651SV, M420KD, M420SL, M470VSE, M550SL, M550VSE, M650VSE & XVT3D580CM LED LCD HDTV Flat Screen Television - Radio Frequency Transmission Works Even Through Walls Amazing Wireless Sound - Enjoy ultimate sound with the 40mm drive units that deliver rich deep bass, powerful ferrite magnets that give you a high fidelity sound and a wide frequency response of 10 - 22000Hz delivers pristine audio, wirelessly. Noise reduction process works that the transmitter compresses the audio signal and converts it to RF signal. The headphones convert received RF signal to an audio signal and decompresses it, reducing noise picked up during transmission. Radio Frequency transmission works by sending out radio frequency signals from the transmitter (base) to the wireless headphones. Radio frequency signals allow high fidelity sound reproduction and have an expanded reception range (up to 150ft) that does not require keeping the headphones within line of sight of the transmission, thus enabling listening pleasure even through walls. Three individual frequency channels with auto tuning gets you the clearest reception with no interference at all. The supplied rechargeable nickel-metal hydride battery lasts approximately 25 hours on a full charge and recharges automatically when you place the headphones on the base station and fully recharges an empty battery via fast recharge electromagnetic induction in just three and a half hours. Also has the option of using standard AA alkaline batteries. (Not supplied) Comfort & Convenience - Durable and Strong, yet so lightweight you can wear them for hours on end, with a easy-adjusting, wide, soft padded headband, king-size earpads that completely cover the ear. Power switch and Volume Control is mounted on the headphones with an ON/OFF LED Indicator. Also the Mute feature operates even when RF signal is weak. Let your mind wander as your feet take you where they will with wireless headphones that fill your world with supreme quality audio.