Motorcycle helmet is a special device used to reduce the head injury of passengers in road traffic accidents. A helmet usually consists of a shell, buffer layer, comfort pad, wearing device, goggles, etc. The shell and buffer layer are the key parts of the helmet to absorb collision energy and protect the head from injury. Goggles can provide good protection for the eyes, Whether the wearing device is "secure" will also have a direct impact on the protective effect of the helmet.

According to different shapes and structures, helmets can be divided into full helmets and half helmets. The main difference between the two is that the protection scope is different. Compared with half helmets, full helmets increase the protection of the lower jaw. According to different application objects, helmets can be divided into Class A helmets and Class B helmets. Class A helmets are suitable for motorcycles with a total exhaust volume of more than 125cc, and have two shapes: full helmet and half helmet; Class B helmets are applicable to motorcycles with a total exhaust volume of less than 125cc. Their volume and weight are smaller than those of Class A helmets, and their shapes are all half helmets. Generally, Class A helmets have better protection range and performance than Class B helmets.