Form your left thumb and left index finger into the letter c. The distance between their tips can be fixed and used as a crude measuring device. A caliper is an insturment made of metal or wood that can accurately serve the same purpose. TUTORIALS CALIPERS TUTORIAL
The thickness of a sheet measured under specific conditions. It is usually expressed in thousandths of an inch (points or mils). Caliper is particularly important when printed materials need to be folded, inserted, and mailed using automatic handling equipment.
A precision tool used to measure thickness, depth, inside diameter, and outside diameter. The measuring units are called mils or points.