Kart Shark- The Kart Shark has the unique feature Boundary Layer Design (BLD). At speed, the BLD helps prevent the helmet from lifting off your head while substantially reducing turbulence. The Kart Shark also incorporates the "Gill" Vent Exhaust System which uses low pressure air to pull hot air from the driver's head. With fiberglass shell construction and nylon lining, the Simpson Kart Shark meets required Snell ratings.