With Hardshell construction ready to take on whatever mischief more aggressive skaters get themselves into, and a 2-stage soft foam liner, it's no wonder there are so many Classic Skate wannabes out there. Look sleek and skate tough in the Pro-Tec Classic Skate Skateboard Helmet. 11 Open Vents 2-Stage Soft Foam Liner Low-profile and lightweight for a snug and comfortable fit. Doesn't meet certification standards for action sports helmets. Transition from soft to hard, away from your head, out toward the hard shell of the helmet. HDPE Flex HDPE is made up of a foam-fitting, high-density polyethylene shell, with flexibility to fit a broader range of head shapes. HDPE shells accompany Pro Tec's 2-stage soft foam liners, not certified to ASTM, CPSC, or CE Safety Standards.