[Compatibilities] Keuaaao X lighted nocks fit arrows with .204 inside diameter, bushings matching for easy installation [Brightness] These nocks emit a vibrant and highly visible light, making it easier to track your arrows during the winter holiday season and in darker evenings. They help in observing trajectory, enhancing accuracy and retrieval [On/Off] The light activates automatically when fired, with a slider switch to shut off. Bowstring-activated linear switch for easy operation [Battery Life] Great battery life of LED lighted nocks: Up to 48 hours. The light remains very bright even in midday sunlight [Practicality] These lighted nocks for arrows are excellent for archery hunting and target shooting in winter, in darker evenings, in bright daylight, and even in 3D tournaments. They help in watching trajectory and finding the arrow. They are a fantastic addition for any archer seeking enhanced shot visibility Color: Green Material: Plastic Package Contents: 12PCS x Lighted Nocks for Arrows Only the above package content is included; other products are not included Note: Light reflection and different displays may cause the color of the item in the picture to appear slightly different from the real thing. Measurement allowed error is +/- 1-3cm