The Stotz taper gages for CAT (SK) toolholder and spindle tapers checks the diameter at 3 levels and reports the angle, the straightness, and the angle tolerance class. They also show the gage line via either Dial Indicator or upgraded to Inductive (LVDT). These toolholders can be used by the toolholder manufacturers or the end user. While the spindle gage can be used by the spindle manufacturer, the end user or a spindle repair facility.