Lately I have been training on my pool game instead of "playing pool" , it has helped me tremendously, I bought this from Outsville, he is a member here on Az Billiards so I wanted to give him a shout out and let anyone interested know how they have worked for me, I had several grave errors in my stroke and perception, What I was seeing as the center of the cue ball was really a hair to right, after fixing that and making sure my stroke was straight, I was still missing too many shots, I was not compensating for english I was using, after fixing that I was still missing certain shots, I thought it might be the same problem as not seeing the center of the cue ball correctly, I didn't want to put the little donuts on the table and then I found this....https://outsville.com/products/on-the-money, I was able to set up shots over and over again without having to leave them on the table and they are easily moved around the table, I was missing a nearly straight in shot over and over again, set up my markers watched how I was missing and finally made one, I then was able to pocket 5 in a row, I then was able to put follow and hit it hard enough to make the shot and move the cue ball to the opposite end of the table, I now know what that type of shot sight picture looks like, another bonus is these can be used at any pool hall, I still have a long way to go but this training aid is helping me get there faster, I don't work for Outsville and I don't know the owner of the company I just know he is a member on this site and this product has really helped my game......if you copy the website address you will get page not found , click on continue shopping and it is right there.