Learn about everything Masterbuilt Masterbuilts 30 Smoker Mat prevents smaller pieces of fish, jerky, veggies and more from falling through the grate of your smoker. Teflon-coated fiberglass. Fits all 30 Masterbuilt smoker racks. Per 2. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Smoker Accessories.