Coaxial Centering Indicator Our Part # ALL-52050 Measuring range: 250 axis feet. Capacity: Internal 5/32" to 4-1/4" dia. or External 0 to 4-1/4" dia. Speed: spindle rotation up to 800 RPM (exceeding this speed is not recommended) Locating accuracy: 0.0005" or true center Includes: restraining rod, center point feeler, 2", 4" & 6" straight feeler, 2", 4" & 6" curved feeler