Oregon 99-107 Mower Blade, 20-11/16" Center hole: 3/8" Requires 1 blade for a 21" cut with a walk-behind mower Requires 2 blades for a 41" cut with a tractor Blade is punched and can be used with Oregon high-lift deflector 79-732 Enhanced hardening to keep the blade sharper and more durable Made to exact OEM specifications