The Firenock lighted nock, at its core, can withstand up to 30,000 shots. In between your first shot and your 30,000th, however, you may desire to exchange your arrow for another (or another or another or another.) With these Firenock Accessories, such as the replacement nocks, practice weights, extreme shock end caps, and o-rings, you can switch up your entire setup with little to no trouble.