The Lumenok R300 Lumen-Arrow Bolt Pack features a .300 ID shaft and is equipped with replaceable batteries. These lighted 20-inch bolts are ideally used for rail-free style crossbows such as the Ravin crossbow lineup, are equipped with Blazer vanes and come in various nock colors. Unique Snap-loc technology assures the archer that the bolt is secured to the string, lessening the opportunity of a misfire or malfunction. Lumenok lighted arrow nocks contain no switch or any other moving parts, and there is nothing attached to the bow to activate them. They contain a simple circuit that relies on the conductive material in the arrow shaft to activate it. Unlike other lighted nocks that use bobber lights designed for fishing, Lumenoks are built inside a real nock with a larger, brighter LED and are durable enough to be shot thousands of times. MSRP: $99.95/Three-pack. Contact: www.lumenok.com