This hook is based on the RepRack Filament Storage System and works on the same spacing with the same ½" EMT pipe (~19mm outer diameter). It uses both pipes of the system to add stability to the hook but can be moved anywhere in the system and will even work in the middle of a partial spool of filament. Add this hook to your system and reclaim your closet as a closet or hang any other items (dependent on print strength) to the underside of your RepRack System to increase its versatility. Hats, coats, bags, headphones, cords, etc… the possibilities are endless.