Carbon Express Maxima RED 4mm Arrow Shafts 300 Spine 12 Pieces Black. Its RED Zone with Tri-Spine Technology manages dynamic spine through the shot cycle for faster recovery and cleaner steering. The 4mm profile helps reduce wind drift and supports deeper penetration while 360 degree spine consistency promotes uniform shaft-to-shaft performance. Straightness is rated to +/- 0.002 inches max with a +/- 1.0 grains weight tolerance for repeatable accuracy. Specifications for Carbon Express Maxima RED 4mm Arrow Shafts: Manufacturer: Carbon Express Color: Black Fabric/Material: Carbon Diameter: 4 mm Features of Carbon Express Maxima Red 4mm Shafts: 4mm Micro-Diameter Arrow Shaft Red Zone With Tri-Spine Technology Manages Dynamic Spine Through The Shot Cycle Faster Arrow Recovery Cleaner Broadhead Steering Reduced Wind Drift Enhanced Penetration 360 Degree Spine Consistency For Uniform Shaft Behavior Straightness: +/- 0.002 Inches Max Average Straightness: +/- 0.001 Inches Weight Tolerance: +/- 1.0 Grains Components: Bulldog Nock Collars4mm Aluminum 50 Gr Outserts Package Contents: Carbon Express Maxima RED 4mm Arrow Shafts Carbon Express CX05752: Maxima RED 4mm Arrow Shafts 300 Spine 12 Pieces Black