72mm 608 bearing tube for filament spool

As simple as it gets, I'm surprised this isn't on Thingiverse yet (and should be a "Customizer" option). Simple roller tube; insert a 608 bearing in either end and watch your filament or anything else roll smoothly.

I used this with the filament spool brackets for the Printrbot Play (file: https://www.thingiverse.com/thing:1161647) and it works great. Only needs 2 bearings instead of 8.