YAHILL Lighted Nocks for Archery Arrow LED Lighted Nocks Compound Bow, 3 pcs of 3 (Red& Blue& Green) 1. 24 plus hours of battery life. 2. Fits arrows with Inside Diameter of 0.24 inch/6.2-6.3mm 3. Piston driven contact switch ensures L.E.D. illumination every time 4. Waterproof and shock resistant design is second to none 5. No assembly required