SPI Deluxe Dial Indicator AGD 1: Dial Diameter 1.65" Features Include... Measuring Range: 0.250" Reading: 0-25-0 Revolution Graduation: 0.0005" Face Counter: Yes Color: White. Accuracy Meets or exceeds Federal Specifications. Easy reading graduations Thread Size: 4-48 Stem Diameter: 3/8" Dial Diameter: 1.65" Adjustable bezel for convenient zero setting with clamp screw. Lug and Flat Back included Certificate of Calibration