This light and strong micro-diameter shaft was developed using cutting-edge carbon manufacturing techniques. This shaft uses fine-tuned spine-to- weight ratios to maximize speed, kinetic energy, penetration, and also to provide the flattest trajectory possible. Black Eagle Arrows Micro-Nock - 8 Grains;Includes Black Eagle Arrows Black Anodized Outserts;.001" Straightness or Straighter;+/- 1 Grain Weight Tolerance;32" Shaft Length;9.6 GPI;.240 OD