Youll always have the correct nock size to fit your arrow shafts when you have Nockturnals Fit Universal Lighted Nock in your archery box. This universal-sized lighted nock comes with three each of S, GT and H sized bushings to ensure a proper fit, while the nock alone fits an X-sized arrow shaft. Outfitted with a patented Linear String-Activated Switch, the nock lights up instantly with shot inertia so you can track the arrow to the target and find it easily in after dark. Stays lit until you reset it. Made of clear plastic, it provides maximum light transmission and can be seen from a distance. Available in nonstrobing Red or Green or Strobing Red/Green that produces about 400 color changes per minute. Per 3. Wt:22 gr. Colors:Green, Red, Orange (not shown), Strobe Red/Green, Strobe Red/Blue. Cancer and Reproductive Harm- www.P65Warnings.ca.gov. Type: Nocks.