Honda OEM Replacement Blade 325-009 
FITS MODELS: HRB215, HRM215, HRS216 and HRT216  with 21'' decks,
Lower mulching blade 
Length 13/16'' (20.6mm)
Centre Hole 3/8'' (9.5mm)
Centre 3 3/8'' (85.7mm)
Width 2 1/4'' (57.2mm)
Thickness .120'' (3mm)