Axe crossbows.166 micro-diameter bolt system, the axe combo bolts with lit axe nock 3-pack system is custom fit for axe crossbows.Cut to length to fit each crossbow model respectively the combo system features the proprietary.166 micro-diameter shaft fletched with three fusion xii sl vanes and the super-bright axe lit nocks.The metal injection molded lit lighted nock system creates an audible click when properly secured to the crossbows string.The super-bright led system is initiated by the forward movement created by the strings forward movement to engage nockturnals 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 nocks 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.Model: Axe 440Length: 19"Weight: 434 GrainsColor: Gray/Orange/WhiteMisc: Super Bright LED NocksQuantity: 3 Bolts and 3 Lighted NocksVane Type: Fusion XII SL