The only measurable difference between the D3 Composite Helmet and Troy Lee's pricier version is weight. While the D3 composite uses, you guessed it, a composite shell, the Carbon Fiber version uses ... carbon fiber. And while there is a weight savings with the carbon, in terms of safety, the D3 composite lives up to all CPSC 1203, CE EN 1077, CE EN 1078, ASTM F1952, and ASTM F2040 safety standards. The D3 features titanium hardware to keep it lightweight. Unlike many one size fits all helmets, the D3 is available in a range of sizes. This means that it will fit your head perfectly, providing the best chance of minimizing damage from a crash. The comfort liner is removable and replaceable and is constructed from CoolMax and Dri Lex to keep your head dry and cool while you're riding. The ventilation in the shell utilizes an intake and exhaust port design, allowing air to move through the helmet to assist in cooling. A total of 20 ports are designed into the helmet. In case of an emergency, the D3 also features quick release cheek pads to remove the helmet quickly.