The H10-76XL headset is designed to provide the ultimate in comfort and communication clarity for safe, quiet flights. These headset are designed to withstand the rigors of military cockpits. New super soft, double foam headpad New comfort gel, undercut ear seals Advanced ENC technology provides 17 - 22 additional dB beyond already superior passive noise attenuation Versatility of portable battery powered or permanent mount options using the same headset Headband custom adjustment for perfect fit Dynamic, noise-canceling M-87 microphone for clear, crisp communications. Meets MIL-26542/2 (USAF) specifications. Ideal for aircraft requiring a low impedance microphone Microphone terminal impedance nominally 5 ohms "FAIL-SAFE" operation. Electronically independent earphone drivers permit uninterrupted communication should ENC or its power source fail PORTABLE BATTERY POWERED - uses a portable battery powered module providing up to 20 hours of use.