Zinc plated. Choose from three series for the appropriate load required. FOB Shipping Point. Steel surcharge may apply. Wheel Description PAYVULC - Black mold-on rubber. PLEXITE - Black phenolic. MIRATEK - Red 95 duropoly. PAYRON - Cast iron steel. BRONCO - Gray rubber, Alum center. PAYDUCTILE - Cast high tensile ductile iron. PAYTHANE - Red 95 poly, metal center.