Sony MDR-RF4000K Headphones

• 40mm driver units for deeper bass and less distortion
• Ergonomic design improved comfort and sound
• Wireless 2.4GHz digital RF signal transmits up to 100 feet
• Storage case works as charging dock
• Up to seven hours of listening on a single charge

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 Easy connection with supplied audio cable