[Compatibilities] Keuaaao X lighted nocks fit arrows with .204 inch 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 low-light conditions, including darker evenings and winter months. Ideal for monitoring arrow trajectory and improving shot accuracy and retrieval. [Activation] The light activates automatically upon release when contacted by the bowstring, featuring a linear switch design for reliable performance. A slider switch allows easy deactivation. [Battery Life] Long-lasting battery life provides up to 48 hours of continuous illumination. The LED remains highly visible even in bright daylight conditions. [Practicality] These lighted nocks are ideal for archery hunting, target shooting, 3D tournaments, and practice in various lighting conditions, including dawn, dusk, and full daylight. They enhance shot tracking, trajectory observation, and arrow recovery. Color: Red Material: Plastic Package Contents: 12 x Lighted Nocks for Arrows Note: Light reflection and differences in display screens may cause slight variations between the color of the item in the photo and the actual product. Measurement may vary by +/- 1-3 cm.