The Custom F Style Firenock Lighted Nock System (3) allows customers to take full advantage of the interchangability of Firenock. Pick from nock color (three colors), LED function (hunting, intermittent/blinking, target), LED color (six colors), and battery type (BL/BR). Optional accessories like AG0GEL and matched weight packs are also available for a reduced price. Will come as five plus separate packs. The OC O-ring pack is included.