Printrbot Extendible Spool Holder Spacer

Tthe Printrbot XL tower spool holder is much wider than most spools. When feeding filament, the spool tends to drift to the left causing uneven feeding. I made this little spacer to keep the spool running true.

I also found it use full to put some automotive paste was along the top of the spool holder so the spool moves smoothly.

EDIT: My original version of this is 40mm long which was appropriate for the spools I had at the time. I have since gotten some filament that came on different s