Plastic Sheeting mes in a wide range of thicknesses. It is rated with the term, "mil". A mil is a measurement that equals one-thousandth of an inch, or 0.001 inch. Most human hair is One-thousandth of inch, or 0.001 inch. The most mmon size in the thickness rating for plastic sheeting is 6 mil. This is 6-thousandths of an inch, or 0.006 inch.