Sennheiser HD1 Headphone with Momentum Wireless Around Ear Headphones Black, NOB ———— Contents: Come with accessories in retail box. New Opened Box Condition. ————- Closed back, around-ear design featuring Bluetooth 4.0 technology and immediate pairing to smart devices using NFC connectivity for wireless freedom. Connectivity Technology: Wireless NoiseGard hybrid active noise cancellation blocks ambient noise using 4 microphones for ultimate isolation to dramatically improve sound quality in noisy environments Sensitivity as per 121 TR 9-5:-