The Ten Point Alpha-Blaze HPX Lighted Crossbow Nock is a crucial component for crossbow hunting, ensuring that your arrows are visible in low-light conditions. This innovative nock features a one-piece design with an integrated LED unit, eliminating the need for assembly. The durable construction withstands high speeds, making it suitable for crossbows that fire at 515+ FPS. The nock retention groove provides a secure connection to the string, allowing you to feel and hear the engagement. With fast shipping, you can get your hands on this essential accessory quickly. The super bright LED light offers superior visibility, while the 24-hour battery life ensures extended use. This product is required for use with TenPoint rail-less crossbows, such as the TRX 515 and TX 440.Key Benefits and Features: Nock Type: One-piece HPX Nock / LED unit Speed Approval: 515+ FPS approved Battery Life: 24-hour battery life when activated Activation Method: Bowstring activated Deactivation Method: Easy deactivation by pulling the nock straight out