TenPoint Alpha-Blaze Lighted Nock - 3 Pack - 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. Essential for Crossbow Hunting Easy-to-use one-piece Nock/LED Unit Unmatched durability Super bright LED provides superior arrow flight visibility 505+ FPS approved Bowstring activated Easy deactivation 24-hour battery life when activated (approximate) Features TenPoint’s Alpha-Nock (all TenPoint & Wicked Ridge crossbows require the use of an Alpha-Nock) Fits all TenPoint & Wicked Ridge arrows with an HP Aluminum Busing