50cm Pushbutton with 2.54mm plug
These handy pushbuttons are great for rapidly connecting to your pet Arduino. With 50cm (approx 20 inches) of wire and a 2-pin 2.54mm (0.1") plug on the end they are simple to use. And the action on them is nice and definite. A good click without being hard to press.
The plunger is 2mnm x 3mm rectangular and easy to attach a custom 3D printed or resin modelled button cap to.
You can even remove the wires and mount the buttons directly onto a PCB.
And yes, they were originally PC power switches.