Bohning's Classic Nock is perfect for wood, fiberglass, and swedged aluminum arrows. The Classic Nock features a raised index and is available in 5/16" and 11/32" sizes. The average weight of the 5/16" is 10 grains, and the average weight of the 11/32" is 13 grains. The Classic Nock's tapered .115" (2.92mm) throat provides the ideal soft snap onto traditional bowstrings. Proudly manufactured at the Bohning Factory in Lake City, Michigan, United States.