Hardcoat-anodized aluminum end controls absorb shock loads and prevent damage to the car. They feature free-rolling, large-diameter aluminum sheaves with Torlon® roller bearings housed in a unique center cage. UV-resistant, carbon-black Delrin® balls carry sideloads. 2:1 purchase. Torlon is a registered trademark of Solvay Advanced Polymers L.L.C. Delrin® is a registered trademark of E. I. du Pont de Nemours and Company or its affiliates.