1. Supported measuring range 0 0.15, resolution 0.0005. This CO AX coaxial centering indicator can quickly and precisely set the center for drilling and milling on horizontal or vertical machines. When the pin rotates, the dial faces the operator, enabling centering. 2. Operation from horizontal to vertical machines and from inner diameter to outer diameter is possible by simply replacing the inductor without modification. When the machine spindle rotates, the display remains steady in any desired position, allowing the operator to use both hands to accurately position the worktable. 3. The central measuring indicator is a measuring tool that uses a lever to transfer the relative position from the workpiece center to the display, converting it into the angular displacement of the pointer. It is a precise, practical, and visible tool for finding the relative center of the machined part, such as the circumference and inner hole of the workpiece. 4. Shaft: 3/8'. Capacity: 5/32' to 4 1/4' inner diameter or 0 to 4 1/4' outer diameter. Rotation speed: Spindle rotates at 100 RPM. Exceeding this speed is not recommended. This is a professional indicator for finding the center of a workpiece on a drilling or milling machine (alignment) and the side diameter center.