Spring tension knurled nut for easy depth measurement and locking. Fitted with 6 inch/150 mm stainless steel rule graduated 64 on one side and 0.5 mm on reverse. Rule measures 7/32 inch (5.5 mm) wide and .041 inch (1.05 mm) thick. Angular depth gage can be used as a protractor for measuring angles 15°, 30° and 45° which are marked on the tool.