This is a mulching blade for your lawn mower. It is located underneath the lawn mower deck, and cuts the grass by rotating. This blade has a curved style shell, and includes extra cutting surfaces along the edges of the blade. If installed correctly this part will keep the grass clipping under the deck longer, and re-cut them. The blade is 21 inches long, and sold individually.
Videos For installing this part.
Replacing your Mulching Blade
Manufacturer Part Number: 942-0741A