Experience high fidelity at altitude with Sennheiser headphones recommended for aircraft cabin entertainment systems. Featuring either active noise cancellation and/or a closed cup design to reduce ambient noise levels, the cabin entertainment selections produce excellent sound quality in a high noise environment.This ultra-light, open-air active noise cancellation headphone is designed with the frequent business traveler in mind. Sennheiser's exclusive NoiseGuard technology actively reduces low-frequency cabin noise by up to 10 dB allowing the user to enjoy their favorite music at a much lower and safer volume level. This active noise compensation functions according to the physical principle that noise and "anti-noise" (exactly reversed in phase) cancel each other out. So, now you can enjoy your music undisturbed, without having to turn the volume up so high that surrounding noise is completely drowned out.