I've already made the third one! It's a homemade filament spool. I used bearings, so it rotates smoothly. Less likely to tangle. You can use it when purchasing filament without a spool, like in Figure 4. It will be shipped in the state shown in Figure 2. Please assemble it referring to Figure 3. Filament is not included. Only the spool is for sale. It can be used with the Bambu Lab A1 mini. I haven't confirmed compatibility with other models.