I purchased the Universal Fit Nock (3 Pack) from FeraDyne Outdoors in green and used them for my first season of hunting. I loved them, and they fit my strings perfectly while tuning (ABB Premium Series). I have a hard time seeing my arrow placement even at 40 yards, so the lighted nocks made it great for target practice. I did break two of them by missing the target and hitting some gravel. They seem to be a little delicate, but if you're a deadeye then you shouldn't have a problem. I stopped using them just because of the expense, and it got annoying having to take my knife out to turn them on and off.