Dial Test Indicator & Universal Magnetic Base Set Dial Test Indicator Features... Range: 0 - 0.030" Reading: 0-15-0 Contact Point: 0.080" dia. X 1/2" long Graduation: 0.0005" 2 dovetails: 3ƒ??8" and 1ƒ??4" dia. Certificate of Calibration . Magnetic Base Features Two universal ball sockets permit adjustment to any angle or position with full 360?ø movement. Fine adjustment clamp. Dovetail and 1ƒ??4" holes for test indicators. Knurled knobs and lock screws.