This is a 3PDT, Three Pole, Double Throw, Latching Foot Switch.
That means there are three independent "circuits", pressing the switch will toggle all the circuits between their A and B connections connected to the respective common.
Sometimes called "On-On". Or of course you can use it as an "On-Off" by leaving one side disconnected.
Check the photos for a crude electrical diagram if you are still not sure what this means!
Commonly used in guitar effects pedals, but of course there are plenty of other things you might want a foot switch for.
12mm Hole. No Markings, No Rating, Not For Mains Use.
Note the pins may be oriented contrary to the direction you would expect given the appearance of the construction, use your multimeter to confirm, and look at the diagram in the photos.
I'm not a guitar player, or an analog guy, nor do i have highly tuned auditory superpowers, so, yeah, I can sell you the switch but don't ask me about how it sounds!
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