The Carbon Express Mach 5 5mm Carbon Arrow Shafts are constructed of a 100% high-modulus carbon for lightweight strength and durability. Features 0.001" straightness for consistent, accurate performanceSpine options: .400 (5.8 GPI), .350 (6.4 GPI), .300 (7.2 GPI), .250 (8.1 GPI), .200 (9.3 GPI)40-grain two-piece aluminum outsert for added front-end strengthBohning Alpha Vanes for stable, controlled flight360 spine alignment for improved broadhead accuracy and repeatability