Blue Wonder Gun Black Kits are similar to the Gun Blue kits, except that they produce a dark, glossy black finish on any carbon steel. No expensive tanks or heat sources required. Kit Contains : Blue Wonder Gun Black– 2 Oz. Blue Wonder Developer - 0.5 Oz. Blue Wonder Gun Cleaner - 1 Oz. Blue Wonder Disotec XFR - 0.5 Oz. Notes: Contents should allow refinishing 4 to 6 long guns. Metal must be heated with a propane torch or hairdryer Applies a "factory-like" black finish. Will not affect existing black; only adheres to bare metal. Contains selenious acid, phosphoric acid, gold, silver, copper and nickel. Not for use on aluminum or zinc alloys.