Fits any bolt with inside diameter 6.2MM，Turn on and off easilysame plastic color as the lightWeighs only 20 grainsBattery life: up to 20 hoursColor :RedPackage : 12pcs light nocksThe luminous light makes it easier to seeLightweight and precision-balanced for superior accuracyPiston switch and easy ON/OFF designWaterproof and shock resistant design，Plastic nocks and stainless PisitonShot placement recognition and arrow retrieval. Indexed nock end provides added safety.Adjustable barrel end is easy to install and provides reliable performance fit.