QualityParts From Oregon That you can depend on. Center hole: 21": Requires 3 blades for 60" cut; High-lift: The aggressive blade angle increases air flow to push debris up-and-out for superior bagging or side discharge; Stays sharp and durable for longer; Fits Bush Hog models: ATH, FTH; ; Oregon Equipment Parts 91-537 Blade Grasshopper 21In[345]