The Carbon Express LaunchPad Precision Lighted Nock is a performance nock created to the strictest tolerances in order to perfectly align from the bow string to the arrow. Because of the precise contact points, aligned nock barrel and concentric design, any arrow will shoot straighter and more consistently with the LaunchPad precision nock. The release-activated, high-visibility LED is amazingly bright and features a lightweight, long-lasting battery that doesn't reduce arrow front-of-center. 4-axis straightness to within .001 inches. Fits all Carbon Express carbon hunting arrows and most other standard sized carbon hunting arrows.