David Clark H10-13X aviation headphones in good condition, no cracks or deep scratches *missing 9v battery cover -M-7A noise-cancelling electret microphone provides clear, crisp transmission -NRR – 23dB passive noise reduction. Additional 17-22dB low-frequency noise attenuation when ENC is activated -In-line stereo/mono switch -Stereo compatible for use with stereo intercom and cabin entertainment systems -Expanded, super-soft, double foam head pad -Larger, yet lighter, undercut Comfort Gel ear seals -Battery Power Module – One 9 volt battery for up to 25 hours of operation -Exclusive patented flex/wire boom for easy, precise microphone placement -Reduced headband pressure -Pilot selectable automatic Shut-Off feature