Our 13 x 20 2 Mil Poly Bags are the standard weight and the most popular thickness for shipping parts, clothing, food storage and more. S-3101, PB539, 539. All 13x20 2mil polybags are made from low density polyethylene and can be recycled. Our flat open top 13 x 20 .002 plastic bags feature impressive clarity and make storage and organization simple for industrial, food service and healthcare applications. These light weight plastic lay flat 13 inch by 20 inch bags can be sealed by using twist ties, bag tape or by heat sealing, and they meet FDA requirements for use in food packaging and storage applications.