Filament Guide Locking Part for Wanhao i3

A locking insert for the "Filament Guide for Top Spool Holder" by Grezmel (see http://www.thingiverse.com/thing:979847).

I loved Grezmel's design over the other filament guides, but the filament did have a habit of finding its way out of the slot on the front, especially when the head was raised in the Z.

This is just a little part I designed to snug-fit inside the filament loop on the guide to completely secure the filament inside. I've created it so that there is a smooth entry and exit