These RAVIN .003 R18 crossbow arrows are made for one crossbow: the Ravin R18. At 16 inches instead of the standard 20, they're sized right for the R18's compact design. Won't work in other Ravin models or the R500 series, so make sure you've got an R18. The 350-grain weight (with 100-grain field tips sold separately) hits harder than lighter arrows. Pure carbon construction keeps them straight within .003 inches. That tight tolerance means your arrows fly the same every time. High-impact brass inserts thread in your broadheads or field tips without stripping. Aluminum nock bushings handle the force better than plastic. The included Ravin polymer nocks work with their clip-on system, and the 2-inch offset vanes keep these arrows flying straight even at the R18's high speeds. This 6-pack gives you enough crossbow arrows for target practice and outdoor sporting events. Remember to use only Ravin-branded arrows with Ravin clip-on nocks so everything works right and stays safe.