Coon's modification of Ham's F-12 was developed for culturing hybrid cells that were produced by viral fusion. The modification consists of doubling the amino acids and pyruvate and including ascorbic acid. The salt concentrations have also been altered. The formula contains 0.863 mg/L zinc sulfate, which may render it unsuitable for culturing mouse L-cells.
Formulated to contain 11.5 grams of powder per liter of medium.