The 9" (230mm) angle grinder is a large, capable angle grinder that is designed to tackle more challenging angle grinding jobs. These tools are designed to make deep cuts and therefore are useful tools for those that work with stone regularly. However, 9" angle grinders are also designed to cut and grind metal and other materials. Typically, the larger the blade, the slower it wears out, so these 9" grinders tend to be good tools for heavy-duty, frequent work.