The Bohning H.E. Nock has a double lock throat that holds your arrow securely in place and allows for a cleaner release. The recessed indexer on the nock aids in streamlining the aerodynamics for a more consistent arrow flight. Each Bohning H.E. nock is made from a long lasting and durable polycarbonate. They fit H diameter shafts (.231" ID). Each H.E. arrow nock weighs approximately 10 grains. Available in translucent colors of Apricot, Electric Blue, and Kiwi. Please specify. Sold by the dozen. Double lock throat for security and a clean release Recessed Index Made of durable and impact resistant polycarbonate OD of .231 fits H-Series shafts