This is a Dial Indicator geared to make 10 full rotations for every inch of stroke in the plunger. The indicator is held together using machine screws and is made up of four gear components, a body, a top (dial surface), a needle, and finally the plunger. The primary function of the indicator is to measure precisely the displacement of the plunger. This was designed for the OSAT Project, for MSE4777 Course at Michigan Technological University Full Page: http://www.appropedia.org/Dial_Indicator#Dial_Indicator