I designed this to solve the problem that 3D pens have no system to feed filament, instead letting it hang from the end of the pen.
The spool is perfectly sized so that you can roll on the filament 'sample size' for pens. It works very smoothly in use.
The spool fits the popular DIKALE pen and anything the same size, but also has a desktop stand if it doesnt fit your pen, or if you simply prefer it.
Everything screws or clips together, no glue is required.
Be sure to read the post-printing instructions to put it all together.