Gage blocks are manufactured to precise tolerances. They are used for calibrating, checking, and setting fixed and comparative gages. Gage blocks are available in hardened steel, carbide and ceramic materials. Types of gage blocks include angle, square, rectangular, and wear. Angular gage blocks are manufactured to a precise angle for gaging angles or for checking angle gages and protractors. Square gage blocks do not have a central hole and are held together with an external gage block holder. Rectangular gage blocks have one or more centrally located holes for mounting on holding bars. Wear gage blocks are used on the ends of the gage block stack that contact the parts or variable gages being evaluated.