MHC 607-4905 Co-Axial Indicator Description : Co-Ax Indicators Inch Range : 0-3 x 0.01mmCO AX INDICATOR provides a simplified method for centering a workpiece or fixture on HORIZONTAL or VERTICAL machines, EXTERNAL or INTERNAL diameters also with N C, EDM and other hard to turn spindles. The face of the indicator remains stationary in any desired position while the machine spindle rotates, thus leaving the operator with both hands free to accurately position the machine table by coordinated movement of the table positioning controls