Bell Impel Adult Bicycle Helmet Fits head sizes: 54-58 cm Fusion Construction for lightweight durability with 18 vents for an extra cool ride Flocking gives this helmet a textured feel which is soft to the touch Quickly adjust to your custom fit with our Rapid Dial feature Triglides, along with a side-squeeze buckle, allow for easy strap adjustment BaseGuard-enhances durability and aesthetics