Phenylbenzimidazole sulfonic acid or ensulizole is a water-soluble UVB absorber that can be utilized in the water phase of emulsion systems, in contrast to most oil-soluble sunscreen ingredients, allowing for a less greasy, more aesthetically pleasing formulation such as a daily use moisturizer containing sunscreen. Phenylbenzimidazole sulfonic acid boosts the SPF of organic and inorganic sunscreens. It can also be used in clear gels owing to its water solubility.

WKSORB550 is an efficient oil soluble broad spectrum UV filter, also is an excellent light stabilizer.