QualityParts From Oregon That you can depend on. Center hole: 5/8": Requires 3 blades for 48" cut; Tungsten carbide is “fused” into the blade – creating an ultra-hard layer at the cutting edge and increasing the time between sharpening; X-Tended Cutting Length™ optimizes the cutting efficiency with each revolution; The aggressive blade angle increases air flow to push debris up-and-out for superior bagging or side discharge; See fit guide for major brand replacements; Oregon Equipment Parts 92-737 Blade Excel / Hustler 16-1/2I