Filiment Color Indicator

I don't always know what color filament I have in any of the printers I can connect remotely with, so I wanted to create something simple to let me know what color filament I will print. I wanted a bit of weight on the holder as just placing a piece of paper would sometimes blow out of frame with a fan or a/c running. You don't really need support structures but you can get stranding on the top of the slot if you don't.