The Scamp II is Giro's smallest helmet designed for young riders, but it still goes big with features and style. Taking design cues from adult helmets, this lightweight in-mold helmet features impact-dissipating EPS foam with a sturdy polycarbonate shell, plus 13 vents for efficient cooling power. The Roc Loc(R) Junior fit system provides extra adjustability with a simple-to-use dial for several years of head protection for fast-growing rippers. Whether they're rolling along in a trailer or powering the pedals themselves, Scamp II is going to make kids want more bike time. Features: Adjustable youth bike helmet Roc Loc Jr.(TM) Fit System is a simple, durable, dial-fit system specifically shaped to match the curvature of a child's head A large, rubberized knob makes it easy for adults to adjust the helmet for proper tension, allowing kids to quickly start their ride In-mold polycarbonate shell with foam liner for maximum safety 13 vents and internal channeling offer optimal breathability Reflective rear decal helps keep your child visible in low-light situations XS: Complies with the US CPSC Safety Standard for Bicycle Helmets for Persons Age 1 and Older (Extended Head Coverage) S: Complies with the US CPSC Safety Standard for Bicycle Helmet for Persons Age 5 and Older Sizing: XS: 45-49 cm S: 49-53 cm