4-1/2” x 7/8” Zirconia Curved Edge Flap Discs are designed to allow the operator to sand and grind on flat surfaces AND within the difficult angle of a fillet welds or other hard-to-reach corners without changing their abrasive disc or tool. Each curved edge flap disc is made with premium self-sharpening, zirconia abrasive grains, resin on resin bonded atop an X weight poly/cotton cloth. This material is this cut into strips and layered on top of one another in a partially overlapping pattern. Finally, the edge of each flap is curled, providing these BHA flap discs with their signature fillet weld flap disc shape. This construction allows for consistent cutting action and extremely long useful life because as flaps are worn away, new fresh abrasive grains are exposed to keep on cutting. Simply put, these 4.5 inch curved edge fillet weld flap discs feature the high quality materials and time tested design of Black Hawk Abrasives best-selling 4-1/2” flap discs but now with the added benefit of a rounded edge. This curved edge allows you to grind using the side and the bottom of the flap disc, not skipping a beat when going from stock removal to edge chamfering to sanding weld seams or slag regardless of location in tough right angles. These radial flap discs are designed to be used on an angle grinder and are particularly effective at grinding steel, stainless steel, cast iron, titanium, nickel and other ferrous metals. Available in 40, 60, 80, and 120 grit.