Gold Tip Laser III 20-Inch Bolt Shafts (Pack of 12) 1 dozen black carbon crossbow shafts 8.5 grains per inch with a +/- 2 grain weight tolerance Bohning Mag nocks, includes both moon and flat nocks and 110 grain brass inserts 20" shafts have a straightness tolerance of +/- .005" and have an outside diameter of .343" and inside diameter of .300" Nock colors vary