This is a filament spool holder designed to fit inside a food dehydrator / filament dryer. It can accommodate common 1 kg spools as well as larger spools such as a 3 kg spool.
It is based heavily on established designs but adds adjustable barriers on the sides of the spool to hopefully prevent the filament unwinding off of new spools.
The build as shown in the pictures uses four 608 bearings, commonly known as skateboard or skate bearings. It can also be built entirely out of printed parts if you print your own 608 bearings, such as the one found here: https://www.prusaprinters.org/prints/17916