Each Fit nock features ultra-strong, impact resistant, clear polycarbonate nock construction encapsulating two brilliant LED lights that alternate after engagement by the patented string-activated, piston-driven linear contact switch. Like all Nockturnal nocks, the strobing Fit nock is guaranteed to reliably activate immediately when the string is released, and it can be switched off quickly and easily with the newly designed Nockturnal Nock Tool, a small screwdriver or most broadhead tips via an opening in the side of the nock. With well in excess of 20 hours of lithium battery life, each strobing Nockturnal Fit weights approximately 25 grains and will remain brightly lit and strobing for plenty of time for arrow retrieval and can be easily spotted in daylight or darkness. 

• Super strong clear Polycarbonate
• Fits all arrows using x nock and larger
• Adapter sleeves for GT, S, and H nocks