Lightspeed's Sierra Headset delivers all the comfort and audio clarity characteristic of a stereo ANR headset while also providing a host of user-friendly amenities. The Sierra model offers auxiliary audio input as well as Bluetooth cell phone connectivity for easy through-the-headset usage of both devices. Additionally, the Sierra features Lightspeed's ComPriority, which reduces music volume by 80% whenever radio communications are received. A pair of AA batteries deliver electronic noise cancellation (ENC) over a wide low-frequency range, and the unit's integral Auto Shut-off feature prevents inadvertent power drainage when the headset is not in use.For unsurpassed comfort, the Sierra features plush ear seals and durable, impact-resistant, fiber-reinforced polymer construction for lightweight, rugged sturdiness. At just 16 oz., the Sierra can be worn for hours on end without issue. A phenomenal, high-end model that'll stand up to the rigors of any flight environment.