●Easy to use: Nocks can go straight form the package to the shaft in fully operational condition. No prep work needed. Just insert it. ●Automatical lighed nocks: The Nocks will automatically light when you are shooting. ●Long lifespan: The Battery can be used for more than 24 hours. High visibility and long lasting batteries life. ●Applications: Fits all arrows with inside diameter 6.2mm shafts. ●Premium material: Our lighted nocks are made of high quality plactic, durable and lightweight.