Fat Daddio's Cookie sheet Available in Standard 14 gauge or HEAVY DUTY 10 gauge Hard Aluminum Anodized for Safety & Durability The Ultimate Cookie Sheet! Fat Daddio's Professional bakeware is covered by an unconditional lifetime warranty against defects, failures, or workmanship issues.Fat Daddio's baking pans are anodized. This anodizing etches the surface of the pan removing inconsistencies and impurities from the natural aluminum. Further, anodizing penetrates the surface of the metal creating a surface that is harder than stainless steel. It also ensures that the pan is dishwasher-safe and will not stain or discolor like natural aluminum pans. Additionally, anodizing will not alter your baking times or temperature.