Size Description: This is a small lightweight off-road helmet, S: 52-53CM, M: 54-56CM, L: 57-58CM, XL: 58-59CM Out of range is not suitable for wearing! Helmet Size Tips (1)Wrap a measuring tape around your head about a half-inch above eyebrows (2)Take measurement two to three times to pick the largest one. The helmet is the perfect choice for city and travel, with a wealth of standard features and top performance in terms of comfort, size, safety and functionality. The ideal helmet for people looking for full-helmets with aesthetic and safety features and the practicality of an open helmet. Because the streamlined chin guard fits perfectly into the outer casing, the chin bar is in the closed position and the performance is full-faceted. It contains S, M, L, XL inner lining, S, M, L, XL size, all can be used. The size of the helmet is mainly adjusted by the inner lining