DIAL INDICATOR, .0001- .025® FEATURES Three measuring heads are attached to the stainless steel rule (blade),allowing versatile measurements on various types of workpieces.The measuring heads are hardened.Economy sets not including a protractor head are also available. Technical Data Square head: Used to set the rule at 90 degrees or 45 degrees to an edge of a workpiece.Center head: Used to locate centers of round workpiecesProtractor head: Used to set the rule at a desired angle to an edge of a workpiece. Also used for measuring angles.