QualityParts From Oregon That you can depend on. Center hole: 3/8": Requires 2 blades for 42" cut; Stays sharp and durable for longer; The aggressive blade angle increases air flow to push debris up-and-out for superior bagging or side discharge; Replacement for major brand: MTD; ; Oregon Equipment Parts 98-499 Blade Mtd 942-0499A 21-3/16I