Perfect ring to the world World reference recald. The Rosenkranz original flexible cable is designed from the bare wire to reproduce the various emotional expression of the music as it is, and is named "Music Alliance Recable. As the name suggests, it reduces electrical burden on various earphones, players, amplifiers, and more, while delivering the charm of music and the excitement of live play to you. This Flex cable was developed at the same time as Rosenkranz's flagship earphones, RK-Silver/HB, designed to bring out the music experience in different product categories. Flex Series allows you to enjoy the difference in sound due to different plating/membrane. Copper Flex: Sounds with a bit of crisp, energetic sound. Tinned Flex: A model with a great overall bunch You can feel the harmony of the beautiful live playing. We have posted feedback from our people using Flex in the form of a review contest. We also have detailed information on development and design, so please check this page from Rosenkranz. http://blog.livedoor.jp/kaisersound/archives/cat_408041.html, Rosenkranz, has been designed to meet the compounding of sound research over 40 years. The Flex® series is not a better product for music fans. Enjoy the music experience through this cable. This product is a twist mechanism, so if you apply pressure in the opposite direction of the twist, the twist will break. Please be careful when using.