Rollers for muscle rack filament spool rack

Made a print in place bearing to go on the dowels for the muscle rack filament shelf as I noticed at least with the dowels I bought with certain spools there was a bit more drag than I'd like on a spool that's being actively used. You'll need 4 per spool and they just slip onto the dowels. 
For those that might want to use this for other projects, the inside diameter is sized for 25mm rods/dowels