Sennheiser HD 660s Audiophile Headphones (B-Stock) - Discontinued bluetooth Perfectly drive any headphone/IEM with

Perfectly drive any headphone/IEM with 4 levels of gain and up to 15Vrms output

2m 392-strands silver-plated monocrystalline copper

Type  Circum-aural closed-back headphones Impedance 35 Ohms Sensitivity 101dB SPL / 1mW @ 1 kHz THD 0

and when combined with how open-backed headphones usually look

then look no further

Sennheiser HD 660s Audiophile Headphones (B-Stock) - Discontinued bluetooth Perfectly drive any headphone/IEM withHD 660S The perfect blend of power and control. The powerhouse open back headphone Connects you to the deepest corners of your music collection. Hi fidelity sound Open back design 42mm transducers Luxurious comfort Detachable cable A Direct Connection To Your Music Known for their engaging signatures and liquid smooth response, HD 660S predecessors HD 650 and HD 600 shattered performance barriers in the audiophile headphone category. The HD 660S