A guarded secret of old-time pros meeting modern technology in the XCalibur One Knocker TM A perfect engineered lipless crankbait that emits a fish attracting, rhythmic knock with its single forged tungsten/ lead weight while pushing an enormous amount of water as it vibrates over grass and other structure. The One Knocker rattle is especially effective on highly pressured bodies of water where big bass get accustomed to seeing every type of rattlebait known to man.