Special Features: Passive General Aviation FAA TSO Approved C57 Cat. B and C58a H10-13.4 Impedance: Standard NRR: 23dB Earphone Type: Dynamic Noise-Canceling Mic: M-7A Amplified Electret Earphone Impedance: 150 ohms(300 each; wired in parallel) Mic Impedance: 50 ohms +/- 20% 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: PJ-055 (.25" phone plug) Mic Plug: PJ-068 (.206" phone plug) Boom Type: Universal Flex Cord: 5 ft.Straight Headpad/Hardware: Super-Soft, Double-Foam Headpad,Lightweight Hardware Weight/Headset Only: 16.5 oz.