Commentaire: Per the vendor there was a change made to the original design of this filter. The new design return filter is 100% backward compatible for service replacement. The original return filter design had a 15mm thread which screwed into an external bypass adapter fitted to the return tube. This external bypass adapter was 15mm on the filter end & 12mm on the return tube end. The new design return filter has a 12mm thread with an internal bypass so the external bypass adapter is no longer required. If your machine is equipped with the external bypass adapter it must be removed before installing the new design return filter with internal bypass. The new design return filter does have a 12mm thread & will screw directly onto the return tube.