The Craftsman 21 in. Advanced Mulching and Bagging Blade delivers greater mulching and bagging performance. The unique design reduces the size of grass clippings by up to 50%. This results in fewer dumps when bagging grass clippings, which saves time and money. It also helps reduce thatch build-up. The Craftsman 21 in. Advanced Mulching and Bagging Blade produces a more even, cleaner cut that helps to prevent a ragged or frayed lawn. Replaces part numbers 33275 (406712), 33521 (406706), 33363 (180459), 33364 (159267).