FIBERGLASS SHELL AND MIPS-EQUIPPED - MIPS stands for Multi-directional Impact Protection System, which is a leading slip-plane technology inside the helmet designed to reduce rotational forces that can result from certain impacts. X-STATIC AND XT2 PADDING - Quick-drying materials, woven with real silver fibers. OVERBROW VENTILATION - Overbrow Ventilation features intake ports on the brow of the helmet to usher in cool air and push it through the air-channel matrix for full ventilation. INTEGRATED BREAKAWAY CAMERA MOUNT - Seamless camera mount, requiring no zip ties or tape, is engineered to break away upon impact to reduce the risk of injury. SPECIFICATIONS - Suitable for bicycle use only. Sizes: X-Small (51-53 cm), Small (53-55 cm), Medium (55-57 cm), Large (57-59 cm), X-Large (59-61 cm), and XX-Large (61-63 cm) Sizes. Important: always take a measurement. Sizes and shapes can vary, even within an age range. Using a helmet that does not fit can be dangerous; 10 vents and 3 Brow ports.