Lower blade replaces Honda 72511-VE2-000 and 72511-VG4-K00, 72511-VG4-KOO. 15-6431. Fits some Honda 21" Walkbehind Harmony, Harmony II, HRB215, HRM215, HRS216, HRT216. Use with HO6430 upper blade. Be sure to match the part number from the owners manual for the part you are replacing with the OEM number(s) listed.