What is Milliinch?
Milliinch (mil) is a distance unit used sometimes by tape adhesive industries to assign a thickness to the tape. The origin of the word must have been due to some confusion since the Metric system and the English system of units were combined (e.g. milli- is from the Metric system while the inch is from the English system).
1 mil = 1/1000 inch (or) 0.001 inch