"Sennheiser HMD27 Professional Broadcast Headset - over-ear desin, closed back, automatically opening two-piece headband ( a wide headband padding is included that converts the two-piece headband into a compact single..."

"Sennheiser HME 27 Professional Broadcast Headset - over-ear desin, closed back, automatically opening two-piece headband ( a wide headband padding is included that converts the two-piece headband into a compact single..."

"Sennheiser HMD26-II-600-S Professional Broadcast Headset - dynamic, closed back and on-ear headphone, impedance 600 ohms momo, sensitivity 107 dB SPL/1 kHz, 1V, frequency range 20 - 18000 Hz, microphone: typ BMD 424,..."