This spool is only compatible with the v2.0 MegaMouth®. A v2.0 reel will be clearly marked with a 2.0 near the logo on the outer cone of the reel. If the cone is not marked it will be considered an original. Otherwise, remove the front assembly and check which bearing you have. A brass bearing indicates a v2.0 reel while a steel and black bearing indicate the original reel.