I was bored and wanted to 3D print myself a butterfly knife, but all of the ones I found needed to be assembled, so I thought I would do some screwing around and make my own, and it turns out it it was very quick and easy to print! Very strong and heavy for being made out of PLA! All parts rotate smoothly and Its very easy to use because of the weight. I've dropped it a couple times from pretty high up and it never broke!