3X4 1.5 mil 1000/CTN Flat Poly Bag. These Prism Pak brand clear flat poly bags are made of 100% virgin Low-Density Polyethylene (LDPE) resin that meets FDA/USDA specifications. Prism Pak brand 1.5 mil poly bags can hold everything from small parts to all types of food items. They can also be heat-sealed to provide security and/or retain freshness. Prism Pak's wholesale flat poly bags are in stock and usually ship within 24 hours.