Ideal for contour work, Long-lasting Aluminum oxide abrasive for fast, cool cuts, use for weld grinding, deburring, rust or paint removal, and feathering. Durable overlapping fiberglass plates for flexibility. Quick change Plastic Speed Hub, Type 27. Application for Aluminum grinding. Wheel Diameter: 4-1/2"; Arbor: 5/8"; Thread size (TPI): 11; 36 Grits; Max. Speed: 13,200 R.P.M. ; Product weight(per wheel): 5oz; Include: 10pcs Warning: always take care and keep away from children. always wear eye protection in work area.