Bags made of 100 gauge High Clarity PVC shrink film and have a small vent hole to let excess air out while shrinking. These bags are 4" x 6" and will shrink up to 40% when heated to 250 degrees. Great for packaging bath bombs/fizzies and soaps. Use heat guns or heat tunnels to shrink. CASE OF 250 SHRINK WRAP BAGS (4" x 6").