The Moore & Wright 420 Series Dial Test Indicators have highly precisioned, fully jewelled bearings and carbide points. There are two dovetail clamps on these models. The 420 Series allow automatic reversal of measuring direction and there is a rotating dial for increased ease of use. Styli Length: 12mm (1/2in).The Moore & Wright MW420-03I Dial Test Indicator has the following specification: Range: 0.030in.Resoultion: 0.0005in.Dial Reading: 0-15-0.Dial Diameter: 1in.