I am sorry for the misspelling. Here is the site https://www.procheckgolf.com/ I have been using this for a number of years, don't play a ball without knowing what # it is. My in season # is a 6 , out of season 5, Very cold 4. This is what works for me. My wife plays an 8 all the time the problem is getting a four peace ball like Pro V1x L- which are 8 all 12 in a box it didn't happen. When we got the procheck years back we came up with a way to check which ball would give her the most distance. We did it on the course with all the # balls from 1 to 8. At that time we were getting the 8 ball from Japan, but they stopped making it. MGS test telling us about the ball for swing speed brought us to Pro V1x L-
I hope this will be of some help.