The Megabass Vibration-X Smatra lure is designed with a small profile and lighter weight. This lure is perfect when the bass are eyeing small baitfish like bluegill and shad. The One Knock model has a unique sound that is different from a rattle. The sound is made by a single moving weight. This lure is great for those harder fishing times like post-frontal, or bluebird-sky days. This lure works well around shallow grass, points, and flats. Works great in mostly all water temps and clarities.