While I was looking for *MasterSpool* compatible filaments I found the wonderful simplistic *SlantSpool* design by **Slant3D**: https://www.thingiverse.com/thing:2850604 This spool prints super easy, faster than the original *MasterSpool* by **richrap** (https://www.thingiverse.com/thing:2769823 or https://www.youmagine.com/designs/masterspool-for-3d-printing-filament-v4) and uses less raw filament. There’s only one part in the design you have to print twice. The two halfs of the spool connect with a simple latching system. Unfortunately the *SlantSpool* is designed for 1 kg refill coils so the 850 g refill coils available in Europe don’t work well on it. The **CarbonoidSpool** is a hybrid of *MasterSpool* and *SlantSpool*. It uses the same latching system like the *SlantSpool* (which I had to clone in Fusion360 because only the STL files are available). Every spool half has 6 filament attachment points for a total of 12! per *CarbonoidSpool*. It works with 1.75 and 3 mm filament. There’s also a place for the sticker that comes with the filament refills to label the spool properly. *CarbonoidSpool* is designed for 850 g refill coils. I also made a bigger version for 1 kg refill coils. The 3D models, STL and more fotos are also available from my GitHub repo: https://github.com/Carbonoid/CarbonoidSpool