Featuring dual phase push-pull drivers of different diameters (13 mm and 10.4 mm), the ATH-CKR90iS in-ear headphones deliver amazingly clear Hi-Res Audio. In the unique push-pull system, the drivers face each other, but are wired out of phase, providing lower harmonic distortion and improved damping and bass frequency control. The use of drivers with different diameters improves high-frequency response. The strong yet lightweight machined aluminum housings reduce unwanted resonance, and their design positions the drivers for optimal performance, while ensuring a comfortable fit with excellent sound isolation. The performance is further enhanced by high-precision stabilizers that ensure linear diaphragm movement for faithful high-resolution audio reproduction. The ATH-CKR90is headphones also include a detachable 1.2 m (3.9') cable with A2DC (Audio Designed Detachable Coaxial) connectors at the headphones for exceptional durability and optimized audio performance. And the cable's in-line controller and microphone lets you easily answer calls and control music and video playback. Four sizes (XS, S, M, L) of interchangeable eartips are included to provide a customized fit and improve sound isolation.