The Lumenok lighted arrow nock is activated upon the shot to allow you to follow the path of your arrow. This Lumenok provides up to 40 hours of illumination and can be seen from a long way. No magnets required for activation. Made using a Burt Coyote .204" nock. Fits .204" inner diameter 24-grain weight Provides up to 40 hours of illumination Runs on replaceable battery 3 Pack Order today!