1. With a measuring range of 0 to 0.15 and a resolution of 0.0005, this COAX coaxial centering indicator can quickly and precisely align the center for drilling and milling on horizontal or vertical machines. When the spindle rotates, the scale faces the operator, allowing them to center it. 2. The centering dial indicator is a measuring tool that uses a lever to transfer the relative position of the workpiece center to the dial indicator and converts it into an angular displacement of the pointer. It is an accurate, practical, and visible tool for locating the relative center of a machined workpiece, such as the circumference and inner hole of the workpiece. 3. Operation can be switched between horizontal and vertical machines, as well as between inner and outer diameters, by simply replacing the inductor. While the machine spindle rotates, the display surface remains stationary in any desired position, allowing the operator to have both hands for precise table positioning. 4. Mounting shank: 3/8'. Capacity: 5/32' to 41/4' inner diameter or 0 to 41/4' outer diameter. Speed: Spindle rotates at 100 RPM. Exceeding this speed is not recommended. This is a professional indicator for locating the workpiece center on a drilling or milling machine (alignment) and the side center diameter.