Filament Spool Holder (under Table)

I build this Thing to put my Filament Spools with less Space as possible under the Table where my printer is. It can be used everywhere.

There is one for the every outside and one for the middle. You can put as many you want in the middle and so you have all spools side by side.

I used my thickest spool to define the distance between the holders. I created a extension which can be plugged into the holder then to use smaller spools also.