Optimized to print on any Makerbot printer! This is an external, adjustable spool holder designed to work nicely with any of the myriad standard spools around these days. They keep the new narrow 5th Gen Makerbot Spools happily upright and balanced, as well as massive 5lbs spools from bulk distributors, and the standard 8inch and stockier 5inch 2lbs spools. Print two frames, four bearings, and four bolts, set them opposite one another and rest your spool between them. Settings: 80% infill and 2 shells for the bearing and bolts. 25% infill and 3 shells for the frame.