Case designed for Adafruit's 3" speakers. Example here: https://www.adafruit.com/products/1314 Holes are designed for M3x10mm screws. The holes are designed for 2.5mm so they can be tapped, but usually printers will have them coming in a bit small depending on nozzle size. Drill out the holes in the base (if necessary) to 2.5mm and tap with M3 tap. Lid will clamp the speaker in place.Print parts with wall thickness 2mm+. This allows extra material if you need to drill out the holes a bit before tapping. Ream out base holes to 2.5mm dia if necessary (only if your printer made the holes too small). Once the holes are 2.5mm dia, tap with M3 tap.