Mount these indicators to a lathe tool post or a height gauge with the included attachment, also known as a universal shank. Half of the measurement scale on the dial face is highlighted yellow to make measurements easier to read. Also known as test indicators, they have a lever-style contact point that pivots as it comes into contact with a surface and a balanced dial with positive values on one side and negative values on the other side. All have highly sensitive, wear-resistant jeweled bearings for a long service life. Rotate the dial face for viewing at multiple angles. The ratcheting contact point can be adjusted to various angles.