Sony MDRRF4000K Wireless RF Headphones

Unplug and enjoy. The MDR-RF4000K digital wireless headphones system gives you the freedom to travel up to 100 feet from your sound source while delivering phenomenal sound. This system includes Ni-MH rechargeable batteries, 2.4GHz RF digital transmission and headphones with a 40mm driver for deep bass. Includes charger and ultra-long battery life.
Differences in details 40mm drivers deliver deeper bass, lower distortion and wider dynamic range.
Battery life for extended viewingThe supplied rechargeable NiMH battery lets you enjoy up to eight hours of continuous on a single charge1. The slim, folding design fits snugly into the charger (included). Substituting a single AAA battery for the rechargeable NiMH pack provides 10 hours of power.
Listen from a distanceRadio Frequency (RF) transmission sends signals from the transmitter to the headphones, allowing high fidelity sound reproduction. You can enjoy the accompanying reception range – up to 100 feet – even when you move outside the line of sight of the transmission.
Stay comfortable as long as you listen
A wide, self-adjusting headband distributes the headphone's weight over a wide area, reducing pressure and improving comfort.
 
Wireless stereo headphone system for music & movies
2.4 GHz digital transmission
Up to 30-m reception range
Real-time automatic tuning on headphones for best reception of signal
2-way transmitter
40mm driver unit, closed-type headphones
Adjustable headband
Volume control function
Automatic on/off function
Lightweight for long time listening comfort
7 hours playback with NiMH rechargeable battery
Easy battery charging system