Sony MDRRF970RK Wireless Stereo Headphones (Discontinued by Manufacturer) Around-the-Ear, 900MHz RF Wireless transmission, FM stereo sound Induction charging: not direct pin contact for ease Noise Reduction technology to reduce interference Neodymium magnets for higher fidelity sound, The right ear cup has the volume dial and auto-tuning button, while the left ear cup houses the supplied rechargeable batteries Charging time approx 16H; Battery up to 14H, Works with Television