Filament tags

So I love this print Stackable Filament Storage Rackhttps://makerworld.com/en/models/979148-stackable-filament-storage-rack#profileId-952502 But my problem is when you put a spool in without the box. It is impossible to figure out if it is PETG, PLA, etc. Which is why I made this. Basically I can put this up next to the spool and I can quickly see across the room if it is PETG, PLA, TPU, etc. I tried to make this as simple and easy as possible.