Fly like a butterfly, sting like a bee! I have printed this in a few different brands of PLA and PETG. Best results achieved with Esun Silk PLA(this filament flex a lot, this feature protects the handles from breaking while assembling the knive to the handles, because you need to flex the handles a bit during the process, if the handles are printed in a brittle materials they can snap during assembly, which is annoying. i used 4 walls, 4 top layers, 4 bottom layers, 15% infill is fine ( i used 35% infill for knife and lock, the change in print time and material use is not even significant, thats due the design dimensions and 4x walls/ top layers/bottom layers). its durable enough at 15%. use brim for handles to prevent warping. (i tried to print with PLA without brim, it warped badly. Just use a brim).