Sennheiser HMDC 27 Professional Broadcast Headset - over-ear desin, closed back, NoiseGard (active noise reduction) reducing the noise level by additional 15dB, no batteries needed, supplied with power through phantom powering (P12 bis P48), automatically opening two-piece headband ( a wide headband padding is included that converts the two-piece headband into a compact single piece for conventional wearing), swiveling ear cap for single sided listening, microphone can be worn either on right or left hand side, ActiveGard (on/off switch) for protected hearing against noise peaks > 110dB, impedance 600/200 Ohms (ANR on/off), max.SPL 128 dB SPL/1 kHz, frequency range 8 - 18000 Hz, microphone: Typ BMD 434, hyper-cardioid, impedance 300 Ohms, frequency response 40 - 18000 Hz, sensitivity 0.5 mV/Pa @ 1 kHz, includes wind and pop screen and cable clip, weight: 240g, attention! cable not included! compatible cables: #448028