Camel CGW brand 4 1/2" diameter grinding wheels A24N have a soft bond construction for fast stock removal. They are made of Aluminum Oxide grain and have a depressed center (Type 27). 1/4" thickness and a 5/8" arbor with hub. Grain Size: Course Grade: Medium. Applications: ferrous metals such as iron, steel, welds, etc. and low grade stainless steel. For angle grinders.