Each safety helmet should have the following four permanent marks: manufacturer name, trademark, model; year and month of manufacture; production certificate and verification; production license number.

There are 2 number wheels on the inside of the hat brim. One of them is a growth ring with an arrow pointing to a certain year. The other is the moon wheel, and the arrow points to a certain month. The combination is the year and month of production.

The validity period of the helmet: calculated from the date the product is manufactured. Among them, plant branch woven caps should not exceed two years; plastic caps and paper and rubber caps should not exceed two and a half years; fiberglass (vinyl fiber steel) rubber caps should not exceed three and a half years.

A safety helmet is a shallow dome hat made of steel or similar materials worn to protect the top of the head. It is a protective equipment to prevent impact objects from damaging the head. It consists of a hat shell, a hat lining, a lower cheek strap and a rear hoop. The cap shell is hemispherical, solid, smooth and has a certain elasticity. The impact and puncture kinetic energy of the striking object are mainly borne by the cap shell. There is a certain space between the cap shell and the cap lining, which can buffer and disperse the instantaneous impact force, thereby avoiding or reducing direct damage to the head. Impact absorbency, puncture resistance, lateral rigidity, electrical insulation, and flame retardancy are the basic technical performance requirements for safety helmets.