The X-Jammer-27™ Pro is engineered to be the ultimate indoor 20-yard spot target arrow. With a 27/64" diameter, X-Jammer-27™ Pro is the largest diameter target arrow in the Carbon Express® line. It also has the maximum diameter shaft allowed in most sanctioned tournaments. Features the BullDog™ nock collar for added strength and protection. Straightness: ± 0.0025" max. Weight tolerance: ± 1.0 grains Patented Diamond Weave – unparalleled spine consistency Spine selection tolerance: ± 0.002"