They definitely will NOT work on the ST AXIS. Much smaller ID on the AXIS compared to the Super UNi-nocks the Tune-a-nocks are designed to replace.

I still have some of the tune-a nocks. They tend to produce a very weak arrow spine reaction due to how loose they are on most center servings. Get the spine correct and they shoot quite well, but I never saw a speed increase.

They work great with a loop and a peg style loop only head (e.e Scott Rhino) for getting the absolute maximum draw length out of a bow. But I'd rather have a uni-bushing as the tune a nocks are kind of soft and ding very easily (they also will crack some of the slightly smaller inside diameter IC type shafts..like CX, when installing them).