UPDATE:P1 and P2 updated. P1 is longer with a stopper, stronger with a thicker base.Holder:P1 and P2 are parts to print for the holder itself. This is made for spool of 70mm thick with an opening of 20mm.P2 as a space for a screw that can be used with the top right screw of the backside of the printer but can also support itself on the top of edge of any of the walls of the printer.If P1 is difficult to slide into P2 you can sand sides a bit but ideally it should not become too loose.Extension:P3 is optional and printed twice. It's clipping on the spool directly and is used as an extension of the spool sides to prevent the roll from unloading on the sides. It is very possible you will need to sand the clips to fit your spool size. This is made to clip on a 126mm wide spool. This part is thin and pretty flexible in PLA so you should be able to bend it if needed.When you change spool, simply remove the side extensions and snap them on the new filament spool.There is enough space left to leave the regular 0.75Kg spool in place.