It's a simple cable wrap sized for standard USB cable thickness. I protects the cable ends on the inside to help prevent damage if you toss it in a bag.
I recommend using the pre-supported model with easy to remove supports because I like easy model clean up.
Both the unsupported model and supports are included if you wish to do some adjustments yourself.
I have added a skinny version for thinner USB cables.
The author hasn't provided the model origin yet.