SPI Deluxe Dial Indicator AGD 2: Dial Diameter 58mm Features Include... Measuring Range: 20 mm Reading: 0-100 Revolution Graduation: 0.01 mm Face Counter: Yes Color: White. Accuracy Meets or exceeds Federal Specifications. Easy reading graduations Thread Size: 2.25mm Stem Diameter: 8mm Dial Diameter: 58mm Adjustable bezel for convenient zero setting with clamp screw. Lug back supplied except where noted. Certificate of Calibration