This spool holder is designed like a modular rack, you can to put many spools as you want in vertical form. And for easy changing spool you only need to pull up the roll and change for another one. This model have two options to being used: You can put the modular rack on a table or in the floor. If prefer, you can use the wall mount (incorporated in the design) to put the rack in the wall to a few meter up from the floor. For my next version i want make and integrate A filament guide (1.75mm and 3mm) *A system for stopping retraction. This model is flexible in his design, you can make some accessories and change the configuration for aumentar its productivity. Enjoy!!!!