TenPoint Crossbows Omni-Nock Crossbow Arrow Nocks (12 Pack), 0.284 Inside Diameter (White (HEA-230.12) TenPoints patented Omni-Nock makes other nocks obsolete when it comes to your arrow Nock color is WHITE Fits ANY ARROW with a .284" inside diameter Omni-Nock design features SIX MICRO GROOVES that form three bowstringchannels which ELIMINATE THE INDEXING PROBLEM associated with moon andcapture nocks Channel "holds" the bowstring in place, the Omni-Nock also prevents flat-nock "shoot-over" or "shoot-under", a growing problem with today's narrow crossbows with acute string angles