AGV K3 SV Adult Simoncelli Street Motorcycle Helmet - Multi/Medium/Large The K-3 SV is a great choice for all riders wanting a safe, quality product with sophisticated modern design HIR-TH (High Resistant Thermoplastic Resin) outer shell Two outer shells and four EPS sizes for the most accurate fit; shell and EPS inner shell dimensions optimized using Finite Elements Method (FEM) analysis IVS (Integrated Ventilation System) with wide ducts hollowed into the EPS shell optimized with the help of wind tunnel testing (4 front vents and 2 rear extractors) Utilizes the new XQRS (Extra Quick Release System) for the tool-free shield replacement in seconds