This spool holder extends the existing spool holder on the Ender3 V3 SE. It's a two piece design with the first long piece inserted through the existing spool holder and the second piece screwing on to the first piece, sandwiching the existing spool holder. It is mirrored on the gantry. This was printed on the Ender3 V3 SE using PETG with 3.2mm walls, which comes close to 100% infill. It was designed with a hollow center to avoid unnecessary material at the least structural zones and give you the warm fuzzies to print at 100% infill or thicker walls. No supports needed, but use a raft since it is relatively tall. This holds an extra 1kg spool over your print bed so I recommend using PETG, although I think you could get away with using PLA.