The General Tools 109 Economy Plunger Dial Indicators offer a myriad of uses in your machine shop, from setting up milling machines and lathes to checking the accuracy of a work piece. The highly sensitive plunger detects small imperfections in your stock or machine with accuracy to .001". The 2-1/4" diameter face can be rotated for setting at any point, and includes adjustable limit indicators for marking important readings. There is also a lug mount on the back of the Dial for mounting to a magnetic base.