Digital 80mm (3 1/8 inch) Hand Routers Self Standing Aperture Tread Depth Gauge Magnetic Feet Max Measuring Speed : 1.5m/s , 60in/s Repeatability : 0.05mm / 0.002 inch Accuracy : 0.10mm / 0.004 inch (100mm) Measuring Range : 80mm ; 3 1/8 inch