When launching bike park booters or bombing primitive trails in the foothills, the Troy Lee Designs D4 Polyacrylite Helmet is one of our favorite full-face helmets to shred in. Featuring downhill-level protection, the D4 Polyacrylite helmet is a budget-oriented version of the D4 that has just as much protection as the carbon and composite models. The D4 features a front air intake system to keep us cool on hot days, and the anatomical cheek pads give us a snug fit every time. The D4 is loaded with Mips C2 protection to help reduce energy transferred from an angled impact, and impact energy is mitigated with EPs foam and the polyacrylite shell.