I printed mine out of Biqu PLA and it was fine. Holes have a diameter of 4.1mm. This is tight enough they'll stay where you put them. A couple of the holes I did have to sand slightly with high grit sand paper to get them on the PTFE, this was due to my print warping. Your mileage may vary. I printed 3 and opted to only use 2 to keep the ends sort of free.