1. Aluminum alloy chamber is cutting with only one machine process by diamond blade provides a more powerful bass and clear sound. However, the PTE ring on the edge of the earphone will made it more comfortable and stable. 2. Earphones design is based on the human ergonomics. It will provide more comfort and won’t slip out during exercise. 3. Button on the controller is carefully placed and designed to make easier to identify without viewing. 4. Metal plug surface is made with find tooling mark texture. It’s easy to grab and fingerprint-proof.