Features of all our flat poly bags include: • 100% virgin, high clarity polyethylene film. • Meets FDA and USDA specifications for food contacts. • 1 Mil - Use for economical short term storage. • 1 1/2 Mil - Economical lightweight protection. • 2 Mil - Most recommended bag for storing and shipping parts, clothing and food products. • 4 Mil - Heavy-duty protection for hardware, industrial parts and tools. • 6 Mil - Extra heavy-duty. Puncture resistant.