... 1,3-Dichloro-5,5-Dimethylhydantoin) Content: 98%min Active Chlorine: 70%min High Content, Low Impurity 1,3-Dichloro-5,5-Dimethylhydantoin ( DCDMH )[ Product Name ] : 1 ... ,3-Dichloro-5,5-Dimethylhydantoin ( DCDMH )[ Formula ] : ... with shelf life of two years. DCDMH (1,3-Dichloro-5,5-Dimethylhydantoin)