Made with 100% virgin domestic-made premium Fluoroelastomer FKM polymer. With 66% Fluorine content, Fluorozone? Premium Performance FKM is comparable to A-type Fluoroelastomer products. This material exhibits resistance to a broad range of oils, fuels, lubricants and most mineral acids. It has very good resistance to many aliphatic hydrocarbon fluids that act as solvents for many other rubbers. Also available in Blue and Brown.