Got some cheap Jet filament from Amazon. It doesn't fit stock or any spool holder I have seen. So I designed this one to work with all the spools I've, Makerbot, SainSmart and Jet.
The CAD image is V2, which has R, L indicators are added. R, L correspond to R, L printer heads. Photos are of a previous version, prints with PLA.
This thing was made with Tinkercad. Edit it online https://tinkercad.com/things/kA29GNnKj5I
I printed this with PLA on MakerBot Rep2x. It was the largest successful PLA print for me on Rep2x. Had to baby it the entire time to make sure the filament feeder didn't get stuck.
Simple to print, with no support. 15% fill, 3 shell @ 0.34mm. ABS or PLA. Could potentially go down to 10% fill.