Adafruit 16mm Panel Mount Momentary Pushbutton - Green [ADA1504]
OK, this item is pretty simple - it's a panel mount pushbutton. It's not that exciting, no LEDs, no bells & whistles. But we really like it anyways – look at that lovely rounded shape, that elegant bevel. If you're going to go with a momentary pushbutton, let it be this one!
The button is a normally-open micro-switch. When pressed, the contacts short closed and Bob's your uncle!