Illuminate the high performance TenPoint arrows (not included) used on your advanced TRX 515 or TX 440 Crossbows (not included) with TenPoint Alpha-Blaze HPX Lighted Crossbow Bolt Nocks. Designed to press fit into an HP Aluminum Bushing(not included), this easy-to-use, 1-piece nock/LED unit activates when fired from the crossbow to help you see the arrow's flight path and find it afterwards. This durable nock features a unique retention groove that allows hunters to both hear and feel its engagement to the string on TenPoint's rail-less crossbows. Durable design is rated to handle arrow speeds up to 515 fps and deactivates simply by pulling the nock back until the light shuts off. LED offers up to 24 hours of use when fully charged. Each nock unit weighs 27 grains. 3 pack. Illuminated nocks for TenPoint's rail-less crossbows (not included) Easy-to-use, 1-piece nock/LED unit Press fits into an HP Aluminum Bushing (not included) Activates when fired for increased visibility Handle arrow speeds up to 515 fps Deactivates simply by pulling the nock back