Description: Jie Xi HWYP Automatical GT Lighted Nocks Lighted Nocks feature a string-activated linear switch located deep inside the nock, so it can't fail. Clear plastic for super visibility- can be seen hundreds of yards away. Weighs 25-50% less than other lighted nocks.Fits ID 6.3mm arrow shaft. Method of use: The nock will be lighted by the pressure of tense string. you can use the little tool to push the colorfull part up through the hole when you want to close the lighted led.very easy and convenient to use.