I saw these online somewhere, I think it may have been “Archery talk forum“. Anyway, they got filed away in the murky depths of my mind for some time, and recently I was planning a new string for my bow and thought it was time to make a set. These are easy to make, work very well and are a great addition to my string jig. The pictures should explain it all, but they clamp the string each side of where you plan to serve, preventing the string from twisting with the rotation of the serving jig, allowing you to serve with high tension without twisting up the string. This really helps prevent the peep twisting on the draw. The rubber you see is short sections of push bike inner tube, otherwise it just 10mm bolts, nuts, washers and a bit of flat bar.
Truly, these are so good, I cannot imagine now making a string without them. If you make your own strings, make a pair of these, you will not regret it.
click on pic to enlarge.