Two mulching style blades made by different companies welded on top of each other. The offset on the upper blade is greater than the lower, allowing both to cut at virtually the same height.
The upside: the clippings are smaller than anything available from anyone at the present time, even at the increased forward rate the oversized engine pulley delivers. This assembly puts the well touted, new fangled blades to shame. As for bagging -- even though they are mulching style blades with a reduced pitch, they work extremely well if the debris needs to be bagged as there is 2x their normal pitch, which is far greater than a single bagging blade.
The downside: Starting the mower is much more difficult due to the increased inertia. Mulching thick, tall, or moist grass requires every ounce of horsepower the engine can muster.
