Single Pole, Single Throw, Soft Touch Push Button Foot Switch. Normally Closed.
These come PRE-WIRED with 18AWG leads that are about 6 inches long. A great time saver.
Tip for Beginners: 18 AWG is on the thicker side for most guitar pedal wiring. If you're going to connect these to a standard PCB you might have to thin out the leads a little to get them to fit in the standard solder pad hole that you'll find on most off the shelf fx PCBs.
This is the shorter version of the standard SPST momentary switch.
The shaft diameter is 11.77mm. I use a 12mm bit to drill a mounting hole for these.