Manufacturers commonly describe the thickness of their liners in MILs or Gauges. Some use the terms interchangeably like they are the same. They aren't. MIL designated liners are 6-12% thicker than a Gauge designated liner for the same number. For example, a 25 MIL liner is about 12% thicker than a 25 Gauge liner. This guide shows the differencs to give you a better understanding of what thickness liner you are buying.