Sony MDR-ZX770BT/B Bluetooth Wireless Stereo Headphones with Microphone - Black (Certified Refurbished) Access all of your favorite streaming services from your smart device to your headphones in a single touch with Near Field Communication (NFC).Hands-free calling. A built-in microphone makes hands-free phone calls a breeze. Once your phone is paired, simply press the phone button on the earpiece to accept incoming calls, and press it again to end the conversation.Up to 17 hours of music on a single charge. The built-in rechargeable battery provides up to 17 hours of continuous, wireless music playback. For hands-free calling, you can speak freely for up to 17 hours or up to 450 hours of stand-by.Comfortable fit. To connect with BLUETOOTH device: 1.Place the BLUETOOTH device within 1 m (3 feet) of this unit. 2 Enter pairing mode on this unit. Press and hold the POWER button for 7 secs. Indicator flashes blue and red after you release the button. 3 Pair the BLUETOOTH device to detect this unit. Select "MDR-ZX770BT." Enter passcode "0000" on BLUETOOTH device. 4 Make the BLUETOOTH connection from the BLUETOOTH device.