This is a speaker foot I designed for my Statement II speakers.
They are designed to fit a standard 3/8-16 hex bolt to screw into threaded inserts on the base of a tower speaker.

My speakers are very heavy, so I printed these with a minimum of 6 perimeters and a 75%+ honeycomb infill. PETG, ABS/ASA, or nylon is recommended

These can be easily sanded by threading a nut onto the bolt and spinning it using something like a drill. This makes prep for priming and painting simple.