I wanted a universal spool roller for my new custom printer, with a new Diamind Hotend (3-color mixing hotend) I needed a 3 spool roller that would be easy and quick to change out filament spools - I also wanted the ability to use multiple width and diameter spools - this fit the bill perfectly and rolls amazingly easy with very little resistance. I made the mounts to hold some extra 8mm rod I had lying around and then designed an end-cap/bushing that would fit the inside/ends of 1" PVC & would double to keep the spools from going off the edge, this allows me to cut the PVC to any width, Wrapped it up by making end mounts to hold the bar in place - I use a couple of 8mm washers at each end to keep the rollers from binding. The mounts are currently sized to fit 1" 80/20 extrusion (but could easily be adapted to many other mounts).