ISO 24444:2010 specifies a method for the in vivo determination of the sun protection factor (SPF) of sunscreen products. This International Standard is applicable to products that contain any component able to absorb, reflect or scatter ultraviolet (UV) rays and which are intended to be placed in contact with human skin. ISO 24444:2010 provides a basis for the evaluation of sunscreen products for the protection of human skin against erythema induced by solar ultraviolet rays.