This mulching mower blade is 18-5/8" long with a 57/64" center hole (some list this center hole dimension as 7/8"). It fits 54" Kubota ZD221 models, 54" Kubota mowers with RCK54P decks, and other models calling for one of the Kubota blade part numbers listed below. See the full list of OEM part numbers it replaces below to ensure it will fit your lawn mower properly. Sunbelt B1PD5011 Predator Blade For 54" Kubota Mowers This is a Predator mower blade. That means it is made from Marbain Steel, the best steel a mower blade can made out of. You can expect it to last longer than your OEM blade or other inferior aftermarket blades. These blades are rated the Rockwell "C" hardness level. They wear 33% slower than traditional mower blades and are 40% less likely to bend or break. Perfect for sandy soil conditions, mowing rough terrain, or, best yet, manicuring a beautiful, well-maintained lawn. Made in the USA. This is an authentic Sunbelt XHT/Predator Marbain Steel mower blade part number B1PD5011. Replaces OEM Part Numbers: KUBOTA: K5231-92340 KUBOTA: K523192340 KUBOTA: K5617-97530 KUBOTA: K5617-97590 KUBOTA: K561797530 KUBOTA: K561797590 YAZOO/ KEES: 100341 Dimensions: LENGTH: 18-5/8" WIDTH: 2-1/2" C. H. DIA: 57/64" (Slightly smaller than 7/8") THICKNESS: 1/4" Blade style/lift: High Lift Need assistance? Please reference SKU A-B1PD5011.