Some filament manufacturers, such as Prototype Supply, use a narrower 1kg filament spool that does not fit on the Printrbot Spool Coaster. This simple design is a direct replacement for the laser cut wood bottom that ships with the Spool Coaster. This works great with the Bukobot since it doesn't ship with a spool holder.This is a simple print and should work on most printers with default settings. I printed mine with PLA using 1.5mm layers and a 40% fill.