Melding form and function a luxurious, open-back, alloy structure provide the foundation from which the innovative ironless magnesium driver units emote bold and articulate, high-resolution sound as soft sheepskin for Cleer Next Audiophile headphones and memory foam caress you in comfort. 40mm Ironless Magnesium Driver for Hi-Res Sound, Alloy Construction, Open Back Design for Flawless Audio Reproduction, Contoured Memory Foam Lambskin Earpads, Quad-core, four-conductor cable allows for efficient connectivity for Hi-Res Sound.