Carbon Express Photon 4mm Arrows 400 Spine 6 Pieces Black. Its 4mm profile helps minimize drag and crosswind influence while Tri-Spine Technology stabilizes the arrow at launch for fast recovery and repeatable grouping. Manufactured to a 360 degree spine consistency standard each shaft is designed to tune and fly uniformly from arrow to arrow. Straightness is rated to +/- 0.002 inches max with a +/- 1.0 grains weight tolerance for dependable precision. Specifications for Carbon Express Photon 4mm Arrows: Manufacturer: Carbon Express Color: Black Fabric/Material: Carbon Quantity: 6 Shaft Length: 32.8 in Diameter: 4 mm Features of Carbon Express Photon 4mm Arrows: 4mm Micro-Diameter Arrow Shaft Lightweight Design For High Arrow Speeds Reduced Drag Reduced Crosswind Influence Tri-Spine Technology Straightness: +/- 0.002 Inches Max Average Straightness: +/- 0.001 Inches Weight Tolerance: +/- 1.0 Grains Components: Bohning Alpha VanesBulldog Nock Collars4mm Aluminum 50 Gr Outserts Package Contents: Carbon Express Photon 4mm Arrows Carbon Express CX05723: Photon 4mm Arrows 400 Spine 6 Pieces Black