KRASH Ahoy Mateys Helmet CPSC , ASTM certified Molded Exotuff 3D helmet design Aerodynamic cooling vents Shock absorbing EPS inner shell Adjustable straps Fits heads 21" - 23" ( 54-58 cm ) ASTM and CPSC safety certified For Ages 8+ The matching Nylon adjustable chin strap is comfortable and insures a secure fit Vented, aerodynamic styling allows for great velocity and a comfortable level of airflow KRASH aims to design 'The Greatest Helmets on Earth', or at least the coolest