This switch is an 18A-125V (Replaces Makita 650101-0, 651176-2, 651177-0 and 651143-7) which can be used in grinders and sanders. Switches are commonly replaced parts in power tools. A switch handles all on/off and variable speed functions. They also have a role in electric breaking; they can momentarily reverse electrical polarity. Because switches use mechanical internals, they tend to degrade and wear out over time, eventually requiring replacement.