QualityParts From Oregon That you can depend on. Center hole: 7/8": Requires 1 blade for 21" cut; Use with John Deere: Try-cycler walk-behind mower, 145Z; Superior mulching for bagging and discharge efficiency; Enhanced hardening to keep the blade sharper and more durable; Made to exact OEM specifications; Replaces major brand: John Deere Oregon Equipment Parts 91-443 Blade John Deere M125413