Abstract: The invention is a solid chemical concentrate system of at least two cooperative shapes. The first shape is an inwardly curved bar having an inner opening. The second shape is an insert which is capable of interlocking with the bar by insertion into the bar inner opening. The solid chemical concentrate provides chemical systems having active constituents which may be the same, different but compatible or functionally and chemically incompatible combined within one matrix to provide at least one substantially continuous surface. The system may also comprise an aqueous soluble or dispersible polymeric film cover.