These small single-pole, double-throw (SPDT) slide switches are rated for 300 mA at 50 VDC and make great on/off power switches for low power electronics.
They can also be used as a convenient way to choose between two analog or digital input signals.
The three pins have a 0.1″ spacing that works with standard solderless breadboards.
These switches are sold in packs of 3.