Use the SPI 98-325-4 Mechanical Edge & Center Finder to locate work surfaces quickly, easily, and accurately. Double-end edge and center finder has both conical and cylindrical contacts. Works with flat straight edges, shoulders, grooves, round work, studs, dowels, or center points and scribed lines. Body and contacts are made of tool steel; hardened, ground, and lapped to close tolerances for diameter and concentricity. 0.2" Head Diameter, 3/8" Shank Diameter, 0.0002" Accuracy.