KZ ZAS uses a the unique texture of metal and the luster of resin craftsmanship, delivering sound waves in-phase without distortion at all volumes from driver to ear. Eight times denser than common thermoplastics, it guarantees durability and longevity, in addition to low internal resonance. Are you looking for real high quality sound earphones? 16-Unit hybrid technology flagship earphone and precisely modify the sound details of each segment. 2-pin Interchangeable Cable Design: Wired headphones becomes TWS wireless earphone. Bluetooth upgrade cable and silver-plated upgrade cable are all available. Ergonomic design to physically reduce noise: The soft ergonomic earhooks are designed to fit diagonally into the ear in accordance with the structure of the ear canal, ensuring a secure fit and making them difficult to remove. They are also designed to physically reduce noise and provide a high level of sound isolation, so we can enjoy our music anytime, anywhere.