The sun protection factor (SPF) refers to the SPF sun protection factor, which is a test index for measuring the defense ability of sunscreen products against ultraviolet UVB in sunlight, and indicates the level of sun protection effect that sunscreen products can exert. It is based on the lowest erythema dose of the skin.
The coefficient behind the SPF value refers to a time range in which the ultraviolet light does not cause damage to the skin. The sun protection index for protection against UVA is expressed in PA or PPD.

classification
The low-grade sunscreen sunscreen index is SPF2~6, the intermediate grade is SPF6~8, the high-end sunscreen is SPF8~12, and the SPF value in the range of 12~30 is high-strength or super-high-strength sunscreen.