String nocks allow for consistent arrow placement on your bow string, shot to shot. These string nocks are made of Brass with rolled edges and a plastic liner. Quick and easy to install. Choose Small (8-12 strand), medium (12-16 strand), or large (16-18 strand). Sold in a 5-pack or by the 100 count. Available in Small (8-12 strand string), Medium (12-16 strand string) or Large (16-18 strand string). Please specify.