Type 27 Zirconia Alumina Depressed Center Wheels, 7 in, 5/8"-11 Arbor Hole Size/ DIAMETER: 7.00 INCHES NOMINAL SCREEN GRIT SIZE DESIGNATOR: 24 MAXIMUM SPEED RATING IN RPM: 8600.0 MOUNTING METHOD: SPECIAL FEATURES: MATERIAL:ZIRCONIA/ALUMINUM OXIDE;USED ON RIGHT ANGLE GRINDERS FOR CUT-OFF, NOTCHING, AND BLENDING APPLICATIONS SUPPLEMENTARY FEATURES: THREADED ARBOR HOLE 5/8 X 11 THREADS