Sennheiser Momentum Wireless - Black Closed back, over-ear design featuring Bluetooth technology and immediate pairing to smart devices using NFC connectivity for wireless freedom Noise Gard hybrid active noise cancellation blocks ambient noise using 4 microphones for ultimate isolation to dramatically improve sound quality in noisy environments 22 hour battery life with both Bluetooth and Noise Gard activated to insure performance during long commutes or plane flights technology uses 2 built-in microphones working seamlessly to improve voice quality and remove external noise during phone calls Connectivity technology : Bluetooth 4.0 + EDR