Race - Alloy steel, heat treated protective coated for corrosion resistance. (Low carbon steel with PTFE liners)Ball - Alloy steel, heat treated, hard chrome plated. Grease Fitting available for all sizes. Units are supplied without grease fittings. When a grease fitting is required, specify by adding suffix "Z" or "F". Ex.: XAM-6Z = Zerk Type Fitting XAM-6F = Flush Type Fitting