The Carbon Express 50755 Maxima RED Shaft features Dynamic Spine Control comes from the patented hi-tech carbon material construction that manages dynamic spine in a new way to make broad heads fly better. Maxima RED uses different carbon materials to control arrow flex to the RED ZONE, which is the section of the arrow shaft engineered to contain Dynamic Spine and make a broad head shoot more consistently. Dynamic spine is managed so well it only takes two spine sizes to cover 40-92-pound bows. A broad head moves the center of mass forward on an arrow, which increases the flex of the arrow when launched from the bow and causes this effect to act like "wings" on the front of the arrow. This results in tighter groups with broad heads and makes the Maxima RED the Ultimate Hunting Shaft. All Maxima RED 12-pack sets are sorted and matched for best-in-class consistency with a Spine selection sorting tolerance of ± 0.0025-inches and a weight sorting tolerance of ± 1.0 grains. Every shaft is laser checked for straightness to a remarkable 1/10,000 of an inch so you know the Maxima RED straightness of ± 0.0025-inches is a maximum measurement, not an average.