Gold Tip Laser IV Pro Series 20-Inch Bolt Shafts Flat Nocks (Pack of 6) 1/2 dozen black carbon bolts with 4" vanes 13.9 grains per inch with a +/- 0.5 grain weight tolerance Aluminum GT flat nocks and 60 grain brass inserts included 20" shafts have a straightness tolerance of +/- .001" and have an outside diameter of .347" and inside diameter of .272" Vane and nock colors vary