This trigger type switch has 4 terminals and a locking mechanism and is compatible with several different Makita tools.Note: 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. Aftermarket replacement switches are fully compatible with their OEM counter parts.