Big Horn 18803 On-Off Toggle Switch - (Optional Lock). 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.This On-Off Toggle Switch (2 Terminals) is mainly used on table saws numerous other bench top tools.