Better Splash Spool Adapter for Flexible Filament

These are adapters for the Splash Spool samples of flexible filament I used to sell. My engineer friend JC came up with this design which is much improved over my original design (http://www.thingiverse.com/thing:983932). Print 2 and snap them into place. You can shake the holder and the spool will not pop off. There are 4 different versions with different size holes in the center. The version in the photo is the 1 inch hole