Harvest Keeper® Oven Storage Bags are the thickest and most durable bags on the market today. With a 1 mil thickness, these bags are puncture free, provide a strong odor barrier and will preserve your favorite foods natural flavors and color. The storage bags measure 18 in x 20 in and are manufactured for multiple uses. These bags can handle the heat which makes them great for use with ovens, microwaves, pans and slow cookers up to 400°F. They can also be used in refrigerators and freezers. Proudly made in the USA.