Here is my acid test for any training aid or gadget. Are there any pros using it. Because with the kind of money these guys are playing for now, if it even remotely helps, them guys are all over it. I don't mean endorsement, I mean they use one. Example, heavy club, lot of pros using them, square groove, all over it, they determined they work. Face forward wedges, nada, just a gimick. Metal headed woods, they all gotem now, graphite shaft, dito. Watch them guys closely, if you hear or read about any of them using something and it is not connected to an endosement, it probably works.