This Aftermarket Trigger type switch has 4 internal terminals and replaces Milwaukee 14-78-0525 switch. It is a10A/125V Over Hang Trigger Switch without lock with integrated dust proofing commonly used in high rated bench top and power tools.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.