The Sennheiser CXC 700 earphones was a good challenge on the micro-acoustic design, aesthetics and comfort fit. With the criteria of usage on an airplane, we knew immediately that our main approach had to optimize the exterior form factor to be non-intrusive and discreet. The study on various sleeping positions on an airplane seat and the ear anatomy enabled us to develop the eventual form factor that was fine-tuned closely with the acoustics and structural engineers. Besides the comfort and fit, the CXC 700 ear-canal phones are equipped with the innovative NoiseGard digital system that offer travelers three noise-cancelling profile that enables the adjustment of how the ear-canal phone sounds according to surrounding environment.