Footswitch button for loop/delay/other effects pedals. Verified to work on Donner Deluxe Looper and Ultimate Delay pedals, but should work with any 10mm diameter circular switch. Designed to slip on and off easily but won't rock off on its own.
Print on top flat side of button with ribs pointing up. Make sure your slicer is set in such a way that the ribs show up.