Purchased two 22 inch Mower Mulching Blades. They are the "exact" replacement part numbers as specified in the Sears Craftsman manual. I have had the original mulching blade on my mower for almost ten years. Sharpened it 6 times. It's starting to lose some of it's mulching efficiency. These replacements should last the life of the mower. They are very solidly designed for this application/mower. Plenty of hardened steel. They were a great price and still cheaper, even with shipping, relative to "knockoffs"...Great product, great price.