4 Mil Lay Flat Poly Bags - Heavy-Duty Protection

A 4 mil lay flat poly bag is a clear, open-top plastic bag made from 100% virgin low density polyethylene (LDPE) with a wall thickness of 4 mil, or 0.004 inches. "Lay flat" means the bag has no side gussets or bottom gussets, so it lies flat when empty and is loaded through the open top. It is the heavy-duty option in the lay flat line, roughly twice the thickness of a standard 2 mil bag.

The difference is wall thickness: 4 mil is 0.004 inches thick and 2 mil is 0.002 inches, so a 4 mil bag has roughly double the material and noticeably better puncture and tear resistance. Choose 4 mil for heavier or sharp-edged contents, long-term storage, and repeated handling. Choose 2 mil for lightweight items where cost per bag matters more than durability.

Yes. These bags are made from 100% virgin low density polyethylene that meets FDA and USDA specifications for direct food contact. They are commonly used for bulk foods, baked goods, candy, snacks, and portioned ingredients. No recycled resin is used in the film.

Lay flat poly bags are heat sealable and work with any impulse sealer or constant heat sealer, which creates a permanent, tamper-evident seal. They can also be closed with twist ties, bag ties, or tape when you need to reopen the bag. Sealers and ties are sold separately.

4 mil equals 0.004 inches, or about 0.1 mm. One mil is one thousandth of an inch, so poly bag gauge is always quoted in mils rather than fractions of an inch. On a lay flat bag the mil rating refers to the thickness of a single wall of film.

Food producers, bakeries, and candy makers use them for bulk and portioned product, while manufacturers and distributors use them for hardware, fasteners, and small parts kitting. Retailers and apparel sellers use them for clothing, textiles, and craft supplies, and warehouses use them for document and inventory storage. Prism Pak sells them in wholesale case quantities in multiple stock sizes.