Oregon 595-621 Mulching Blade, Gator G5, 21" Tungsten carbide is fused into the blade  creating an ultra-hard layer at the cutting edge and increasing the time between sharpening. Center hole: 5/8" X-Tended Cutting Length optimizes the cutting efficiency with each revolution. Gator Mulcher provides cleaner, more efficient cutting performance that can eliminate the need to bag, saving time and hassle. Replaces major brands: Husqvarna, AYP, Craftsman, and Poulan. High-lift: The aggressive blade angle increases air flow to push debris up-and-out for superior bagging or side discharge.