Engineered for maximum kinetic energy and greater knockdown power, the PileDriver 20" Crossbow Bolt was built for the hunter who demands the ultimate in penetration. Advanced construction ensures spine consistency for greater accuracy, and the composite material is extremely durable at impact for exceptional reliability and repeat performance. Precision-sorted for straightness and weight, creating reliable consistency shot after shot. Engineered for maximum kinetic energy and knockdown power Carbon composite construction 4" Fusion vanes Green lighted half moon nocks Pack sets are sorted & matched by spine and weight Spine sorting tolerance: +/- .0025" Weight sorting tolerance: +/- 2.0 grains +/- .002 real straightness Universal Nock System: includes inserted lighted moon nocks plus C-Nocks compatible with older crossbows that use a capture nock