Featuring the world’s first dual phase push-pull driver system, the ATH-CKR9 in-ear headphones deliver amazingly clear, high-resolution audio. The unique push-pull system incorporates two 13 mm drivers that face each other, but are wired out of phase, providing lower harmonic distortion and improved damping and bass frequency control. Machined aluminum housings reduce unwanted resonance for crisp mid- and high-range audio, while a stainless steel acoustic resister and a bass acoustic resister provide accurate high-frequency and low-frequency response, respectively. The ATH-CKR9 in-ear headphones also come with four sizes of interchangeable eartips for a customized fit and outstanding sound isolation – another measure to help deliver audio reproduction that rivals the original sound.