The IGNITOR insert design eliminates poor fit nocks. Shot activated ignition with no tool required to reset. 100 percent waterproof. Weigh 36 grains. Lighted crossbow nock available in flat or moon. Simply instal the insert, place the LED in the nock and slide the nock into the insert. Red LED provides 15 hours of continuous light and green provides 50 hours. The LED light sticks are replaceable.