QualityParts From Oregon That you can depend on. Center hole: 1/2": Requires 2 blades for 36" cut; Requires 3 blades for 52" cut; Enhanced hardening to keep the blade sharper and more durable; Made to exact OEM specifications; Replacement for major brand: Bush Hog; Oregon Equipment Parts 92-135 Blade Bush Hog 50056498 18-1