Micro-diameter arrow for ultimate accuracy and penetration with minimal wind drift. The Pierce uses components that maximize concentricity and durability. Straightness Tolerance: +-.006â?쳌, Weight Tolerance: +-2.0 gr. Available in sizes 250 (9.8 GPI), 300 (9.1 GPI), 340 (8.3 GPI), 400 (7.6 GPI), and 500 (6.6 GPI). Includes GTO nocks and Ballistic insert system.