DAVID CLARK COMPANY INC. > HELICOPTER HEADSETS > DC H10-56PRODUCTS > DAVID CLARK COMPANY INC. > HELICOPTER HEADSETS > DCCI H10-56 DC Helicopter Headset - MODEL H10-56 NSN 5965-01-330-4042 Special features: Passive / Helicopter NRR: 27 dB Impedance: Standard Earphone Type: Dynamic Noise-Canceling Mic: M-101Amplified Dynamic Earphone Impedance: 150 ohms(300 each; wired in parallel) Mic Impedance: 150 Ohms Earphone Sensitivity: 90 dB SPL on flat plate coupler, re 1mW input @ 1KHz Mic Sensitivity: 400mV RMS ±6dB into 150 ohm load @ 1kHz for 114dB SPL input Earphone Frequency Response: 200-5,500 Hz Mic Freq Response: 300Hz--3.5KHz per RTCA DO 214 Earphone Plug: U-174/U Mic Plug: U-174/U Boom Type: Hinged Wire Cord: 5 ft.Coil Headpad/Hardware: Super-Soft Headpad Weight/Headset Only: 20 oz.