For motorcycle riders, helmet is a more basic and important protection. When traffic accidents occur, it can ensure that the rider is not seriously injured. However, in the selection and use of helmet, several principles must be paid attention to, especially the expiry date.

There are a number of things to remember about buying and using helmets, especially when it comes to shelf life.

Helmet selection principle：

1. Helmets also have a shelf life: do not choose helmets after 4-6 years of manufacturing date, and be sure to confirm the manufacturing date to avoid being cheated or buying helmets that have exceeded the shelf life.

2. There must be qualified mark, including CNS, DOT, SNELL, ECE, R05 and JIS mark.

Principle of helmet use：

1. The helmet will be changed after 2-3 years. It may be different according to each brand.

2. Do not use the helmet that falls heavily or has a car accident. Even if it is just a small scratch, the appearance is still intact.

Preservation dates and manufacturing dates are key to choosing a helmet, and if you keep it too long, its protection will decline.

As for the reason why the helmet should be replaced after its expiration date, the main reason is that the material inside the helmet is made of plastic PP, ABS and composite material. After a long period of solar irradiation, these materials will become brittle, which will lead to the decline of protection ability. In case of accidents, the knight's head cannot be effectively protected.

When buying helmets, pay attention to whether there is a qualified label.