INTERNATIONAL CLAYS gunpowder is the second in the "CLAYS" gunpowder series of powders, bringing this technology to the 20 gauge reloader. It also works in 12 gauge, 2 3/4" light, medium and heavy 1 1/8 oz. loads, and high velocity 1 oz. As with CLAYS gunpowder, clean burning and flawless functioning is the rule.
Big Book Catalog, Issue:68, Page:544
Sinclair, Issue:5B, Page:094