There is a red adjustable knob on the back of the Skateboard helmet. Turn it to the right to tighten,and to the left to loosen it.
This Skateboard Cycling Helmet has 12 ventilation holes, special aerodynamic design and breathable foam to ensure good ventilation and perspiration during exercise, allowing you to stay cool and comfortable for a long time.
The Skateboard helmet has a three-layer structure to increase comfort and protection. The first layer is made of injected ABS shell, which has high hardness and can resist high-strength impact.
The Multi-sport helmet has a classic and concise matte black finish, light weight, comfortable to wear, smooth venlitation system, and provides higher safety.
The size of the helmet is 10.2*8.7*7 inch and the weight is 370g.Packing list: Skateboard Helmet*1.