I have some on certain arrows. I find them handy in cases where standard nocks are fitting too tightly on the serving of new strings. It's the easiest fix I've found. I shoot 3 under, with a double nock, so they don't grip the serving at all and stay in place. In time the serving wears-in and I can use standard nocks again. The same goes for serving that is too loose for standard nocks. I haven't experienced any negative issues with them as far as shooting. They are more expensive than standard nocks, but I've found having a dozen or two around worth it.