All Portolite Pitching Mounds feature the highest quality materials and cutting-edge design. Portolite uses a poly protected core with fiberglass reinforcements to make their mounds some the most durable on the market. With the unique infusion of materials, they have engineered these mounds to be much lighter and easier to move than a full fiberglass core mound. All of their mounds are covered with the highest quality nylon Astroturf. They offer both a green and clay color for all of their pitchers mounds.