The Standard Linear Low can be used on place of .0015 to .002 low density. The Heavy Duty Linear Low can be used in place of .003 to .004 low density. The Extra Heavy Duty Linear Low can be used in place of .004 low density. The Linear Low material allows the bags to be of a thinner gauge while still providing the same or better strength and puncture resistance as a standard low density bag of a higher gauge. Gusset Poly bags have expandable sides or bottoms which allows for more fill-able space. They are great for irregular shaped items. These are also FDA approved for use in food.