Feature: 1. IMPROVED COMPATIBILITY: These lighted nocks are specially designed for arrows with a 6.2mm inner diameter, ensuring a perfect fit and accurate installation. 2. DURABLE CONSTRUCTION: Crafted from plastic material, these lighted arrow nocks are built to withstand the toughest conditions. They offer exceptional durability and a long lasting performance. 3. EFFORTLESS OPERATION: With a user friendly design, these lighted nocks are incredibly easy to use. Simply attach them to your arrows without the need for any tools, and enjoy hassle free experience. 4. AUTOMATIC ILLUMINATION: The built in LED lights in the tail of these lighted arrow nocks automatically illuminate upon release, providing a clear and visible path for your arrows, even in low light conditions. 5. VERSATILE ACCESSORY: Not just a practical tool for nighttime situation, these lighted arrow nocks also serve as a valuable accessory for quick arrow location during daylight hours, making them perfect for all scenes. Specification: Item Type: Lighted nocks Material: Plastic Weight: Approx. 20g / 0.7oz Battery: 1 x CR425 button battery 25mAh(included) Tail Diameter: 10mm / 0.4in Main Tube Diameter: 6.2mm / 0.2in Length: 4.3cm / 1.7in Length(without shaft): 3.8cm / 1.5in. Package List: 5 x Lighted Nock