Yuhui C-SS7-D is a premium grade gel-type strong acid cation (SAC) exchange resin based on sulfonated styrene-divinylbenzene (DVB) copolymers with standard Gaussian particle size distribution. Its 7% cross-linkage offers the optimal performance on both kinetics and resistance to oxidation. C-SS7-D is developed to be used for industrial water softening when it works in sodium form and demineralization when it works in hydrogen form. Its dark color makes it convenient to be separated from anion resin in mixed bed system.