Dial co-axial Centering Alignment Indicator Imperial Simple method of centering a workpiece, fixture or assembly Find the center on internal or external diameters The outer body and indicator dial remains stationary while the center spindle with the feeler attached rotates. This allows the indicator dial to always face the operator. A retaining arm is included to hold the head in a convenient position. The combination of straight and offset feelers in different lengths allows a large work area to be covered