This item is a two-pack of good quality momentary pushbuttons. When pushed they are "on" and when you release they spring back and turn off again.
They mount in a 12mm round hole (when 3D printing 12.5mm diameter will be easier to insert).
We provide the bare buttons, and also the buttons with 15cm female Dupont cables attached, which makes it very easy to use in Arduino projects.
To use with Arduino, connect one cable to a GROUND, and the other to an Arduino digital IO pin. Set the pin to INPUT_PULLUP mode and use digitalRead on the pin to get the value. A value of HIGH means the button is NOT pushed, and a value of LOW means it is being pushed.