Makita® depressed center grinding wheel, flat heavy duty non-hubbed, 6 in wheel dia, 1/4 in wheel, 7/8 in center hole, arbor connector, WA36N-BF grit, N grade, aluminum oxide abrasive, wheel type number: type 27, 10,200 RPM maximum, applicable materials: non-ferrous metal, stainless steel and steel, white wheel. Makita® A-95978-25 Flat Heavy Duty Non-Hubbed Depressed Center Grinding Wheel, 6 in dia x 1/4 in thick, 7/8 in Center Hole