This is a Trigger type switch that has 4 terminals. This authentic DeWalt replacement part is sold individually. Switches are commonly replaced parts in power tools, handling all on/off and variable speed operations. They also have a role in electric breaking; they can momentarily reverse electrical polarity. Because switches use mechan...Read moreical internals, they will degrade and wear out over time, eventually needing replacement. Some common signs of a broken or failing switch are: • The tool has stopped functioning • it refuses to start. • The tool operates intermittently, requiring multiple tries to turn on, until eventually it won't start at all. • The variable speed function and electric braking aren't working properly.