Carbon Express Nano-Pro RZ Target Carbon Arrow Shafts 350 Spine 12 Pieces Black. This multi-spine construction supports consistent launch behavior repeatable accuracy and forgiving performance in windy conditions. Built from lightweight high-strength 46-ton carbon it is designed to maintain its spine and straightness tolerances over extended use. Straightness is rated to +/- 0.0025 inches with a +/- 1.0 grains weight tolerance and it includes 12 Bulldog nock collars. Specifications for Carbon Express Nano-Pro RZ Target Carbon Arrow Shafts: Manufacturer: Carbon Express Color: Black Features of Carbon Express Nano Pro RZ Shafts: Compound Field Arrow Design Tri-Spine Technology With Stiff Ends And A Flexible Center Section Multi-Spine Construction Manages Dynamic Spine In Flight Forgiving Performance In Windy Conditions 46-Ton Carbon Construction Straightness: +/- 0.0025 Inches Average Straightness: +/- 0.001 Inches Weight Tolerance: +/- 1.0 Grains Includes 12 Bulldog Nock CollarsOther Components Sold Separately Package Contents: Carbon Express Nano-Pro RZ Target Carbon Arrow Shafts Carbon Express 51586: Nano-Pro RZ Target Carbon Arrow Shafts 350 Spine 12 Pieces Black