Lighted Crosbow Bolt Nocks Half Moon Sytle Fits Arrow Diameters .297" - .302" ID Bolt Tracer Nock Fits crossbow bolts with .297" to .302-inch interior diameter. Installs in seconds without glue or tools. Weighs 30 grains. Super-bright LED light with up to 20-hours of battery life 1 Per Pack.