Extremely simple filament spool

This Thing simplifies mass production of spools for filament coils up to 100 m in length and with any coil diameter. It can be made in two sizes, the 30 mm one is nice for ~50 m coils and the 40 mm should fit up to 100 m coils. The spools are made from simple cardboard cut outs and small printed clips. Prints clean and quick.