Test Indicator & Magnetic Base Set SPI Dial Test Indicator Features include... 1" dial diameter Range: 0.030" Reading: 0-15-0 Contact point: 0.080" dia. X 1/2" long Graduation: 0.0005" 2 dovetail stems: 3/8" and 1/4 dia Certificate of Calibration Base Features Include 3-dimesional indicator holder with a unique central locking mechanism - manually adjusts to secure a snug fit. Easy to set up into required position, swivels 360°. Holder includes the adjustment. On/Off switch.