Cal-Hawk Aluminum Oxide Flap Discs, 4-1/2" x 7/8" x 40 Grit, 10-Pack 10 Pack, Max speed: 13,300 rpm 40 Grit. Arbor Size: 7/8". Flap type #27 Perfect for finish work, deburing, and light grinding. Great for use on rust, paint, steel, and non ferrous metal