Made of high quality PP comosite for the best performance.The surfaces of side step is made of heavyweight T-304 stainless steel for lasting durability and maximun strength.Supported underneath by an integrated steel frame for added rigidity. That's how the wider, thinner running board can support more weight than standard tubes. Material:High quality aluminum alloy with hairline surface treatment. Molded nylon composite top surfaces which is a high-strength plastic.