Small toggle switches that can be used for a variety of wiring purposes.
These switches have two positions that internally connect the middle terminal to one of the other terminals on either side of it as the switch is thrown to either side. There's two rows of terminals that work this way simultaneously.
These switches can be found in popular wiring schemes such as David Gilmour's 7 way switch wiring.
Dimensions -
Thread diameter - 5mm
Thread height - 6mm
Body (including terminals) - 13mm
Total height (including terminals, excluding switch shaft) - 23mm