Features： 1、Aerodynamic Design: Streamlined shape offers superior wind resistance with a lightweight and sturdy construction for breathability. 2、Novel Integration Construction: The helmet is fashioned in a one-piece design with an enhanced appearance. 3、Adjustable Comfort: Equipped with a 4-tier height adjustment system for a personalized fit. 4、High-strength PC Shell: The outer shell is made of PC material that is highly resistant to impacts and corrosion. 5、Impact-absorbing Mid-layer: The middle layer is made of high-density EPC foam that effectively absorbs external forces. 6、Removable and Plush Interior: The detachable lining is thickened for added comfort during wear. 7、Adjustable Fit: The knob adjustment system allows for easy adjustment of the circumference for a secure fit. 8、Four-height Adjustment: The adjustment system offers four height settings for a customizable fit, and features a ponytail-friendly design for convenience. Specification： Material: PC shell, EPC foam Colors: Pink, Blade, White, Black, Dark Diorator, Orange（Optional） Dimensions:  M: 25 x 20 x 16cm / 9.8 x 7.9 x 6.3in,  L: 26 x 22 x 16cm / 10.2 x 8.7 x 6.3in Size: M/L（Optional） Weight:  M: 262g / 9.3oz, L: 287g / 10.2oz Package List： 1x Bike Helmet