The FG-17 is an Advanced Fiberglass Composite sport helmet, tested in HJC’s Wind Tunnel Laboratory. The “ACS” Advanced Channeling Ventilation system allows full front to back airflow to flush heat and humidity up and out. The FG-17 has 3 shell sizes (XS/S, M/L, XL/XXL) for a superior fit. SilverCool Interior keeps the rider cool and fresh with moisture-wicking, odor-free and advanced silver antibacterial fabric that is removable and washable. With both DOT and Snell ratings, the FG-17 is the best value on the market for a track helmet in terms of quality and price.