This is one of the fastest, most accurate ways to mark the center of a round, square, hex oval, most any shape that fits into the “V” leg. Fast, precise measurements Dial face indicates 0-90-0-90-0 read 0-90 in any direction Works as magnetic base protractor, level, centering head, centering punch, or pipe centering tool great for pipe fitting and welding. Centering tool has a solid brass movement which gives immediate reading of angles for 360-degree radius. The V base is welded together then, precision milled, very durable with strong magnetic pull. Center pin hardened to RC 59/63 Accurately marks center point at angle being indicated to be drilled, milled, welded... Extra features include: Certificate of calibration included with new or reserviced units Guaranteed 1 year +/- .5 degree All instruments have been calibrated traceable to NIST standards, 1 year service calibration warranty Made in U.S.A.