The Evolution Helmet features TSG's custom low-profile, snug fit paired with super sturdy shell construction. Being one of the slimmest designs available doesn't mean the Evolution Helmet is any less durable than other helmets, its tough skate-style hardshell construction is bonded to an EPS inner core for a two-piece construction that provides high durability and high impact protection. Designed to curve anatomically around the head for a more comfortable, tailored fit with extra pads included in two different sizes allowing you to get the perfect fit. Size guide: Small/Medium: 54 - 56cm Large/X-Large: 57 -59cm XX-Large: 59 - 61cm Size: Large/X Large, XX Large, Small/Medium