You have to also buy the G nock insert for the rear of the arrow. It almost makes them robin hood proof. The inserts fit your standard shafts like Beman Hunters, Easton Lightspeeds, Carbon Tech Cheetahs etc. The G nock pushes into the insert and a little string wax makes that easier. I do all my arrows with G nocks.
I use them on easton aluminum shafts by first cutting off the tapered end of the arrow shaft and then installing a "bushing" with hot melt glue and then the g nock. Allows you to index the nock at whatever position you wish. I feel that the g nocks are sperior to most (just personal preference probably).