Poorly constructed ...
July 13, 2015
This is an excellent concept, however, the product is poorly manufactured.
The cutting dies must be off because the balls don't sit where they are supposed to sit. I'm an instructor and bought a bunch of them. I had to use two sets to make one set. I took the "practice" or "full" piece from a 2nd set and RE-CUT the slot for sliding under a ball in play. Then threw away all of the "pre-cut" "in play" pieces.
That makes an already expensive item twice as expensive, not even counting your time to fix it.
Plus, unless you already know how it should work, you probably won't be able to fix it yourself.