I purchased these blades to replace the black blades that came with the mulch kit (33921) for the Craftsman Pro Series 20438 lawn tractor. Fortunately, I had the misfortune of breaking the original black mulch blades on a large tree root at the end of last season and had to replace them. I purchased these red Craftsman 42" Advanced Mulching and Bagging blades as replacements and they work beautifully. No debris on the cutting deck, no debris on me, no lines of grass clippings on the lawn, all which were a huge problem with the black 33921 blades, and no more frustration. For now on, only these.
Ended up being the wrong star pattern for the mower and after running the mower with the blades on they were damaged and I could not return them. Had to buy ANOTHER SET with proper star pattern. I literally wasted nearly $50 in wrong blades.