The role of wearing a helmet: The reason for wearing a cycling helmet is simple and important, to protect your head and reduce injuries. The person wearing the helmet can stop the head being hit relatively slowly, and if the person without the helmet hits the head on the ground, the brain edema tends to cause hemorrhage, and the balls aggregated in the helmet can absorb the impact force, Avoid these unfortunate events. Wearing a helmet on a bicycle can prevent 85% of head injuries and greatly reduce the degree of injury and accident fatality. Half-helmet riding helmets are divided into road-specific (without brim), road and mountain dual-use (with detachable brim), etc. Use helmets similar to those used for baseball or roller skating. Full-face riding helmets are similar in shape to motorcycle helmets and are generally used by downhill or climbing bike enthusiasts. Cycling helmets generally consist of 7 parts: Hat shell: the outermost hard shell of the helmet. In the event of an accidental collision, the cap shell is the first line of defense to protect the head and is used to disperse the impact force. Cap body: the foam inner layer inside the helmet. It is the second line of defense to protect the head. It is mainly used to absorb the impact force in the accident and reduce the accident injury. Buckle and chinstrap (safety harness): used to fix the helmet position. The straps are fixed under the ears on both sides, and the buckles are fixed at the throat. Note: After the buckle is fastened, there should be 1 to 2 fingers of space between the buckle and the throat. Remember not to be too tight or too loose. Hat brim: Hat brim is divided into fixed type and adjustable type. General road cycling helmets do not have a brim. The function of the brim is to prevent foreign objects from flying into the eyes of the rider, and at the same time, it has a certain shading effect. Air holes: The air holes are to help the head dissipate heat and ventilate, which can keep the hair dry during long-distance riding. The more air holes, the cooler the rider will feel, but the lower the relative safety factor. Generally, it is better to choose a helmet with the right amount of air holes. Knobs: There are knobs on the back of the riding helmet for adjusting the tightness. Riders can adjust the helmet size according to their head size. Padding: The padding can absorb sweat and slight vibrations from the body during cycling.