Product Feature: Detachable Ionic+Silver Ion Antibacterial Lining Antibacterial Test Report Advanced Version Quick Release Magnetic Buckle The Rotating Space Of More Than 90° Built In Biomimetic Keel That Conforms To Shape Of Head Bones Enhancing Head Protection EPS Buffer Layer Disperse The Impact Force Reducing The Direct Impact On The Head 16-Hole Diversion & Ventilation Quickly Wicks Away Heat And Sweat Allows The Wearer To Adjust The Helmet According To Their Own Head Shape And Size