Kensington Bluetooth Stereo Headphones with Microphone Stream music to the headphones from any Bluetooth enabled music phone or computer (requires A2DP Bluetooth protocol) Cord-free, Bluetooth 2.0 connection up to 66 ft. (20 m) wireless range Built-in rechargeable lithium-ion battery for up to 23 hours of non-stop music and 19 hours of talk Built-in microphone Lightweight, comfortable over-the-ear design with ear cushions