Cut-off wheels must be attached to a cut-off wheel power tool designed specifically for the size of wheel used. For safety, cut-off wheels must always be used with a wheel guard that is compatible with the size of the wheel. The cut-off wheel must have a maximum operating speed greater than or equal to the maximum speed of the power tool used. Our General Purpose Cut-Off wheels are easily changed with a hub and retainer nut design when discs become worn. Our 3M™ General Purpose Cut-off Wheel is constructed of aluminum oxide mineral abrasive, a popular choice among industrial professionals because of its fast cut-rate and long life. We chose this mineral because it is a tough, durable abrasive that self-fractures to expose fresh cutting edges in use, whereas traditional abrasives such as garnet quickly wear down with use. Due to its fast cut-rate, hardness, strength, and low heat retention, aluminum oxide mineral is widely used in all types of abrasives. Aluminum oxide is suitable for a wide variety of materials, including ferrous alloys. Unlike abrasive discs, which shape or sand objects using the disc surface, cut-off wheels make a perpendicular cut through the work piece using the outer edge of the wheel. Abrasive cut-off wheels are typically used for cutting through metal, for example auto body or marine sheet metal, stainless steel tubing, exhaust pipes, clamps, propeller shafts, and rusted bolts. Cut-off wheels are attached to a cut-off tool (sold separately) and must always be used with a wheel guard for safety. Our 3M™ General Purpose Cut-off Wheel measures 3 inch (diameter) x 1/32 inch (thickness) x 3/8 inch (center hole).