I shoot Easton Exel 400s and they fit tightly, and work very well. I cant tell any difference in point of impact of the arrows with my regular nocks out to 50 yards. I did have one kick a little as it hit the target and broke off one of the ears of the nock, ruining it. But any nock probably would have done the same. I love them, and cant wait to shoot one on video, at a deer.