Tru-Fire Five Star Center Nock. The Five Star Center Nock is the only nock of its kind which will eliminate serving wear caused by a release. Every size nock and virtually every release will work without modifications. The Five Star Center nock will help keep your arrow on the string while maintaining proper peep alignment. The Five Star Center Nock is CNC machined out of aircraft aluminum for durability. It installs easily with the aid of an allen wrench. Tru-Fire Five Star Center Nock.