I just got one and have shot 3-4 times with it. My bow was extremely quiet to begin with,(Martin Razor X)I noticed very little change in that department. I did take my leeches off and noticed no increase in noise. I haven't shot it without the leeches and STS. I probably won't. I did notice my groups get real tight. The nocks on my arrows snap on the string tighter than nicks I've used in the past. I wonder if this is the reason the STS helped my grouping.I did have to use the serving material rather quickly, because in a matter of just a few shots, my string was beginning to "fuzz". It does beat up my string, but the serving material has taken that away. I also shot broadheads the other night as well. They were dead on grouping, just a little low from my FP, settings. Which is great since i haven't began to tune the broadheads yet.

So in summary, it did very little as far as quieting my bow, only becuase it was quiet to start. It DID improve my grouping, so I am going to keep it for now. For those who don't like them, they have a 30 day return, send it back.