Tape thickness is usually measured in the United States in “mils”, or thousandths of an inch (1/1000”). The thickness can be measured from the bottom of the adhesive surface to the top of the outer surface or simply the film itself. In most cases, the thicker the tape the stronger and more durable it is. This is referred to as tensile strength. Thinner tape tends to be used for lightweight or temporary applications whereas thicker material is required for sealing heavy boxes and other heavy-duty applications. Duct tape is a great example of a thick adhesive roll whereas painting tape is often very thin and hand tearable.