Honda, 21" Set Of High Lift 3-In-One Blades, Fits Walk Behind Models: HRX217 & Most HRR Models, Replaces O.E. Blade Set 08720-VH7-000, Lower Blade 72511-VH7-000, Upper Blade 72531-VE2-010, Blade Dimensions .804" Lower Blade & 17/16" Upper Blade With A Round Center Hole.