Sait Fast Grinding A24N are the United Abrasives grinding wheels providing quick action. They are made of aluminum oxide, a course grain size and a soft bond allowing for fast stock removal. Applications: Ferrous Metals such as iron, steel and welds as well as low grade stainless steel. 4 1/2" diameter, 1/4" thick, Type 27 (depressed center), 5/8" bore, no hub. For right angle grinders.