Carbon Express 50650 Maxima Blue Streak Carbon Arrow Shaft Bare shafts come with LAUNCHPAD Precision Nocks and BullDog Nock Collars (nock color may vary from image) Dual Spine Weight Forward - patented fusion of two different carbon materials that creates 2 spines in 1 arrow Laser checked for straightness to a remarkable 1/10,000 of an inch; Straightness of +/- 0.0025-inches is a maximum measurement, not an average Item specifications: 150-Size, 6.5-GPI, 0.508-inch Spine and 0.284-inch Diameter 12-pack of black finished shafts are sorted and matched by weight and spine for best-in-class consistency