SONY WHXB900N/B Headphones Features Active noise cancellation Effectively blocks out distracting background noises, so you can enjoy a focused, immersive sound environment. Rechargeable battery Offers up to 30 hours of use and lasts up to 300 hours on standby mode. Headset touch controls Include volume, play/pause, next song, going back, tap and hold to activate VA, Quick Attention. Built-in microphone Enables simple hands-free chatting via a phone. Bluetooth 4.2 interface with NFC (Near Field Communication) technology Enables simple wireless pairing with your Bluetooth-enabled device. Supports HFP, HSP, A2DP and AVRCP Bluetooth profiles. Over-the-ear design For a secure fit. 3.5mm gold-plated connector Enables use with a variety of audio devices. 40mm drivers Deliver powerful sound. 3Hz - 20kHz headset frequency response Along with a 50Hz - 8kHz microphone frequency response ensures faithful sound reproduction. 50 ohms impedance To efficiently conduct power. Dynamic transducer design For reference-grade audio. Stereo design Delivers crisp tones. 4' cable Permits a flexible range of motion.