The next evolution in the Day Six arrow line is the XD series shafts. This 5mm shafthas a lighter gpi than their HD shafts for those who want flatter trajectory or higherFOC. Unlike all other 5mm shafts that come with a cheap insert or outsert, the XD shafts come standard with their patented Centric System components as well as a machined nock bushing to reinforce both the front and the rear of the shaft. Just like their HD series shafts, the XD is made to the same tight tolerances to provide for precision tuning and accuracy.