Invisible Thread Reel

Here is my version of a "Invisible Thread Reel".
Most magician will know what is it good for.

I try to work with very thin kevlar threads. But in the standard tube-like reels the ultra thin tread breaks very often. Changing the thread takes me more then 20min. Each time...
So pure time wasting!

In a video with John Finn he showed his old self-made reel. It was contained in a pillbox.

Based on that design I tried different housing-sizes, reel-diameter, rubber-band-length and so on.