Centering test indicator is a new measuring tool using lever to transmit relative position of workpiece center to indicator and convert into pointer angular displacement. It is the accurate, easy and visible tool to find out the relative center such as excircle and inner bore of processed work piece in machining of fabricating machineries. Mounting Shank: 3/8 inch. Capacity: Internal 5/32 inch to 4-1/4 inch dia. or External 0 to 4-1/4 inch dia.Speed: spindle rotation up to 100 RPM. Exceeding this speed is not recommended. This is a professional indicator to find out center (alignment) of workpiece on jig on boring machine or milling machine and center lateral diameters. Supportinf Measuring Range: 0-0.15 inch, Resolution: 0.0005 inch, this CO-AX Coaxial Centering Indicator can Quickly and accurately center in boring and milling set-up on horizontal or vertical machines. When principal rotates, the plate operator throughout for /her to center. Operate at an angle from horizontal to vertical machines and from internal to external diameter without any change by simply changing the feeler. The face of the indicator remains stationary at any desired position while the machine spindle rotates, leaving the operator with both hands free to accurately position the table. Package Details: Coaxial Centering Indicator x 1, Restraining Rod x 1, Center Point Feeler x 1, 2 inch, 4 inch & 6 inch straight feeler x 1, 2 inch, 4 inch & 6 inch curved feeler x 1, Wrech x 2, User Manual x 1, Storage Box x 1. A must-have tool set to meet your needs!, Weight: 2.11092615865 Pounds, Manufacturer: Prterver