Dynax UB, Dynax UC and Dynax-S50 are wax-like coatings to provide protection from corrosion in areas such as the underside of your car and box sections. Dynax-UB is a dark coating, while Dynax-UC is for use in visible areas where a darker coating would detract from the look. Dynax-S50 is optimised for injection into cavities.
All three of these products can be used in all areas, however, they are adapted slightly for intended use. For example, Dynax-S50 has the best anti-corrosion power, however dries soft so does not stand up as well to mechanical wear as Dynax-UB, which is a firmer waxy film.