The M7 QB-905 grinder wheel is a handy tool for most owners of M7 pneumatic angle grinders. While M7's grinding wheels are built to last, they will eventually wear out. This is especially true for anyone with a lot of metal, stone, or concrete to remove. Once your blade goes, it's best to have a replacement handy so you can get back to work. This 5” grinding wheel works with eight air grinders.