Smart Carbon Technology. Unmatched durability, consistency and straightness retention. Smaller diameter and maximum penetration. Straightness +/- .006", weight +/- 2 gr. 500 (7.6 GPI), 400 (9.5 GPI). Accu-Tough Nock installed, Accu-Tough inserts included. Color: Black. Sold by dozen or half-dozen.