Made with 100% virgin USA-made premium Fluoroelastomer FKM polymer. Blue in color to make it easily distinguishable from other materials, Fluorozone? Blue Premium Performance FKM exhibits resistance to a broad range of oils, fuels, lubricants and most mineral acids. Fluorozone? has very good resistance to many aliphatic hydrocarbon fluids that can dissolve many other types of rubber. Also available in Brown and Black.