20-INCH / 415-GRAINS / BALANCED AT 13% FOC / .003 STRAIGHTNESS 3-Pack with Alpha-Blaze Lighted Nocks. The Alpha-Blaze Lighted Nock contains a one-piece Nock/LED unit that is indexed with the vanes and press fits into the arrow s Aluminum Bushing. Upon firing the crossbow, the bowstring s force compresses the two pieces and activates the lighted nock. Deactivate the easy on/off Alpha-Blaze lighted nock by pulling the nock straight out until the light turns off no tools required. The LED light of the Alpha-Blaze system lasts for approximately eight hours when activated. The system features TenPoint s Alpha-Nock HP that is equipped with an HP Aluminum Bushing for increased strength and accuracy. The Pro Elite 20-inch carbon arrow is fletched slightly offset and is fitted with a 46-grain aluminum insert, Q2i Fusion X-II 3.0 Vanes, and TenPoint s new Alpha Nock HP Nock and Alpha Nock HP Nock Bushing. Pro Elite shafts are inspected for straightness to within .003 and hand-sorted for weight tolerance to within 2-grains per dozen. TenPoint s Alpha-Nock features a deep bowstring groove, a large smooth radius base, and elongated ears. The string on TenPoint s crossbows wraps tightly around the center of the Alpha-Nock to yield straight nock travel and precision down-range accuracy, while minimizing string serving wear. The Alpha-Nock s deep groove holds the bowstring in place on extremely narrow crossbows to prevent shoot-over or shoot-under .