Nockturnal lighted nock s-series red 3/pack FEATURES-Red-3 lighted nocks per pack-20+ hours of battery life - you can still find your arrow the next day-Can go straight from the package to the shaft in fully operational condition-Piston driven contact switch ensures LED illumination every time-Waterproof & shock resistant-Fits arrows with inside diameter of .244 Other Features: Piston driven string activated linear contact switch ensures led illumination every time,20 hour+ battery life,water and weather proof nocks can go straight from package to the shaft in fully operational condition-no prep work.Fits most carbon exp,pse, beman ics,easton,etc w/.244 id