Using these Metabo flapper flap discs is easy. First, make sure your grinding tool is turned off and unplugged. Then, attach the disc to the tool following the manufacturer's instructions. When using, keep the disc at a proper angle to the material you're working on. This will help you achieve fast removal and one - step blending. These discs are great for steel, stainless steel, and ferrous metals. Just be careful not to apply too much pressure, as it might damage the disc or the material. When you're done, turn off the tool and let it cool down. To keep the discs in good condition, store them in a dry place. And remember, all 7/8' Arbor wheels come in a pack of 10, while all 5/8 - 11' Arbor wheels come in a pack of 5.