Strike King Pro Model Hard Knock 6XD Crankbaits have the unique curved bills of the XD series that allow the bait to dive deeper and faster, changing the deep diving crankbait game forever. The XD series from Strike King has set the standard for deep running crankbaits. The Pro Model Hard Knock 6XD Crankbaits now have a Free-floating rattle chamber with one solid rattle giving a whole new knock that will give the fish a whole new sound that they can't resist.