New out of the box troy lee d4 composite eyeball flo yellow helmet size xl D4 Helmets D4 reigns king atop downhill podiums and BMX events across the globe. Available in carbon, composite and polyacrylite. Details are what makes the D4 the most coveted full-face in mountain biking. Prioritizing safety while balancing weight through premium construction and materials, D4 incorporates Mips®protection with an EPP chin bar and anatomical cheek pads with emergency release.