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. The LED light of the Alpha-Blaze system lasts for approximately twenty-four hours when activated. Features: Essential for Crossbow HuntingEasy-to-use one-piece Nock/LED UnitUnmatched durabilitySuper bright LED provides superior arrow flight visibility505+ FPS approvedBowstring activatedEasy deactivation24-hour battery life when activated (approximate)Features TenPoint’s Alpha-Nock (all TenPoint & Wicked Ridge crossbows require the use of an Alpha-Nock) TenPoint Alpha-Blaze Lighted Nock for HP Bushing X 3pk Green HEA-379.3