Easton 6.5mm Hunter Classic 400 spine Carbon Arrows - 12 Pack - Hunting accuracy for shooter confidence is the cornerstone of Easton 6.5 arrows. The 6.5 uses proprietary Acu-Carbon Uniform Spine process. Acu-Carbon is a continuous-fed, single-die manufacturing method that results in the most reliable tolerances and eliminates the need for the spine-alignment and weight sorting. Easton's Acu-Carbon production line produces the most consistent spine and weight from dozen to dozen and lot to lot-year in and year out. This benefits the bowhunter with truer flight and pinpoint accuracy in the field. 6.5MM Inserts included-precision machined component has four-times larger shoulder. Strengthens the broadhead/arrow interface and boosts F.O.C. (23 grains) Microlite Nocks-shortens the critical distance between the shaft and bowstring for improved alignment and reduced weight. Acu-Carbon Uniform Spine USA Manufacturing Process for the highest level of accuracy. Bully Vane Fletching-stiffer material for superior control and quiet arrow flight. Straightness .003in