Birchwood Casey Presto Blue Touch Up PenBirchwood Casey Presto Blue Touch Up Pen Ideal to maintain your firearm. It is for touching up small areas like scratches in the metal. It penetrates hard steel instantly and gives a durable blue black finish. Cold blue formulation that works on all steel (except stainless steel) Penetrates hard steel instantly Gives a durable blue black finish that won't rub off Reacts quickly with usually one coat needed No heat required