These are two different sized gears to fidget with. I have printed them out of PLA, PETG and Nylon. The Nylon version worked the best as nylon is nice and slippery. Both of the other materials worked as well but you may have to modify your extrusion multiplier if the gears don't spin freely. They both should print well at 0.2mm or 0.1mm layer height. For assembly they each require 2 screws to hold them together. I believe the large one uses #4 x ¼" and the small one is #2 x ¼".