AirBake Natural Aluminum 2 Pack Insulated Cookie Sheet, no burn design, 14 x 12in & 16 x 14in Air insulation prevents top sheet from overheating which prevents burning Micro-Dome technology decreases bake times by up to 15-percent 100-percent aluminum No rust promise 10 year warranty 100% aluminum construction. No more burningGuaranteed! Guaranteed not to rust. Micro-Dome technology. Dishwasher safe.