While marshalling at the 2012 John Deere Classic, I was cleaning the 10th fairway from range balls that were errantly hit onto the hole from the range. I kept one of the PRO-VI "PRACTICE" balls that was laying in the middle of the fairway. Later that day while playing in my company golf league I used this "practice" ball and got my first hole in one with it. If I can do this in practice, imagine what I could do in the real game!, haha.