dynax UB, dynax UC and dynax S-50 are wax-like coatings to provide protection from corrosion in areas such as the underside of your car and box sections. UB is a dark coating, while UC is for use in visible areas where a darker coating would detract from the look. dynax S-50 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, S-50 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.