Drop these little things into the heel adjustment slots in your bindings and stop the heel cup from sliding around.

Tested on the Union Forces and Falcors, but if your binding uses a similar heel adjustment slot to this, it will likely work. If you try this on another model, drop a comment and let others know what the result was.

Recommend printing these with PETG or ASA so it handles the cold. 

Available with 0.2 (normal) and 0.3 (loose) tolerances.