ABN 4.5&rdquo; x 7/8" T27 80 Grit High Density Zirconia Alumina Flat Flap Disc Grinding Sanding Sandpaper Wheels 5 Pack 4.5 x 7/8" 80 Grit Sanding/Grinding T27 Flap Disc Wheels; Designed for use on stainless steel and aluminum as well as many other surfaces. Ultra-performance zirconia alumina with abrasive for extended disc life and a super aggressive cut. Zirconia alumina self sharpens to extend disc life while also providing more cutting power than aluminum oxide discs. Durable fiberglass back is lightweight, but also offers extra strength and absorbs tool vibration. Disc is semi-open to retard loading on aluminum. Size: 4-1/2&#034; Grit: 80