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 reblue applications. Key Features:- Cold blue formulation that works on all steel (except stainless steel)- For complete re-blue applications Size: 3 fl oz, Plastic BottleNote: This product cannot be shipped to California