Deep, blue-black finish penetrates hard steel instantly. Works great on polished steel that contains nickel or chrome alloys, including mauser-style bolt release buttons. For touch-up or complete re-blue. Available in 3 fl. oz. or 32 fl. oz. container. SPECS: 3 fl. oz. (89 ml) or 32 fl. oz. (.95 L) net contents, plastic bottle.