The UFO X Series Green Lighted Nock provides superior arrow tracking with bright green illumination designed for .204 caliber arrows. This 3-pack offers reliable performance for hunters and target archers.UFO X Series Lighted Nock SystemBright green LED illumination for enhanced visibility.204 caliber compatibility3-pack quantity for multiple arrowsCompact dimensions: 0.60 x 4.25 x 5.45 inches (package)Activates automatically upon releaseEssential for low-light hunting conditions and target practice these lighted nocks help you track arrow flight paths and recover arrows quickly improving your archery experience and success rate.