*Pack of 10 ? Premium zirconium grain on cotton backing ? Grind, blend, deburr, and finish all in one disc ? Free of iron, chlorine and Sulphur compounds ? Resists loading on aluminum ? Larger and more flaps than the competition providing longer life Encore is a general-purpose flap disc with a premium zirconium grain that grinds, blends and finishes. It has larger and more flaps than the competition providing longer life. Resists loading on aluminum and will not contaminate stainless steel. Free of iron, chlorine and sulfur compounds. Type 27/Type 42 discs. Used for stainless steel, titanium and other high-tensile alloys, aluminum, copper, brass, and ferrous and non-ferrous metals such as iron, steel, welds, etc.