westlake market, birchwood casey flat black touch-up paint pen plus presto blue touch-up for gun or any painted metal project plus 5 free cotton swabs westlake market, birchwood casey birchwood casey presto blue - presto mag gun blue is a cold blue formulation that works on all steel (except stainless steel). specifically formulated for when you want a deep blue luster on your firearms metal surfaces. for complete re-blue applications. key features: - cold blue formulation that works on all steel (except stainless steel) - for complete re-blue applications size: 3 fl oz, plastic bottle flat black pen - the super black touch-up pens contain a fast-drying, lead-free paint with superior adhesion and durability that helps fill in deep scratches or worn areas. specially formulated for use on highly polished and matte finished alloy gun receivers, trigger guards, scopes, binoculars, cameras, flashlights, fishing reels and other sporting accessories.