Sennheiser HD 660 S - Hires Audiophile Open Back Headphone

Reference class open back, dynamic headphone employing new and improved transducers delivering low harmonic distortion, Transducers are hand selected for precise (1 dB) left / right matching tolerance insure exceptional accuracy and presentation of stereo spatial characteristics, 150 ohm nominal impedance allows direct connection to home and mobile Hires audio devices. Contact pressure: 6.0 N - 1 N, Para aramid reinforced, detachable cables employ high conductive OFC copper to insure signal integrity with very low handling noise, Supplied with two connection cables: One with a 6.35 millimeter stereo plug, the other a 4.4 millimeter Pentaconn balanced stereo plug. Also included is a 6.35 millimeter to 3.5 millimeter adaptor. Connectivity Technology: Wired 6.35 millimeter / 4.4 millimeter Pentaconn