Low shrink temperature (200F to 250F) and very high shrinkage rate (over 40%) in all directions. It can be used with virtually any shrink machine. (manual, semi-automatic, and automatic) Use heat gun, heat tunnel or a blow dryer to shrink. Unbeatable price and quality To prevent ballooning during shrinkage, a small vent hole is drilled on lower part of each bag. Hole diameter is about 1/16 inch. It is located at about one third of the total height from the bottom