Made of silicone; withstands temperatures from -40 degrees f to 480 degrees f * Measures 11.625 x 16-inches; fits 13 x 18-inch baking sheet; nsf and fda approved * Re-useable for thousands of times; Helps baked goods brown evenly * Nonstick Silicone Baking liner by sil-eco; Safe to go from freezer to oven and microwave oven * Set includes Four (4) Sil-Eco Silicone Nonstick Baking Mats, Half-Sheet Size