AXE CROSSBOW LIGHTED NOCK 3 PACK RED Features: Designed to fit AX405 .166 Diameter Crossbolts Crossbow String Activated Injection Molded Super bright LED 20+ hours Approx. Weight: 44 grains The metal injection molded Lit lighted nock system creates an audible click when properly secured to the crossbow’s string. The super-bright LED system is initiated by the forward movement created by the strings forward movement to engage Nockturnal’s patented crossbow string-activated linear switch with piston-driven assembly. These lighted nocks are exceptionally reliable and do not require any specific tools to set up and come factory-installed in the shafts. Side illumination ports on the nock’s body allow for additional light dispersion and increased “tracking” as the nock moves. With more than 20 hours of lithium-powered battery life the extended burn time grants plenty of opportunity for reuse and easy identification long after the shot.