H2Glo lighted nocks ONLY FIT our Tiger Shark LGT series arrows and red Nock Adapters. They will NOT fit the Fiberglass or Carbon Spined® shafts. To use, just pull out the replaceable nock that comes with the arrow or Nock Adapter and insert one of these nocks. A small switch on the nock turns it on to use or off when not in use to save on battery. Nocks comes in a package of 3 and glow red when lit.