Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4912187.

I wasn't pleased with how the clips flopped around inside the base, so I remixed the base a bit...

No more clips: the rubber band slips over the protrusions inside.

Also added a circular indentation on the front for orientation purposes.

As with the original, no Support required.

Also added an Extender that the Base snaps onto. Gives the target more mass and stability. It features a center located attachment hole.