Post mitochondrial supernatants prepared from Sprague Dawley male rat liver. Prepared using the treatment schedule of Matushima, et. al. 1976. In: de Serres, F.J, et. al., editors. In Vitro Metabolic Activation in Mutagenesis Testing. Amsterdam (NL) Elsevier/North Holland p. 85-88. MOLTOX S9 preparations and cofactor reagents for use in metabolic activation studies are manufactured to rigorous standards of quality and performance and are used by leading industrial, government and academic laboratories worldwide. It is imperative that frozen S9 preparations remain in storage conditions of around -80C, requiring expedited shipping on dry ice and careful temperature considerations during the thaw process. Once thawed your S9 is ready for use with cofactors. *Non Returnable*