Ayp OEM Replacement Blade 340-256
FITS MODELS: 22'' deck
Mulching blade 
Length 21 3/4'' (552.5mm)
Centre Hole 5/8'' (15.9mm)
Outer Hole 3/8'' (9.5mm) 
Centre 1 7/8'' (47.6mm)
Width 2'' (50.8mm)
Thickness .134'' (3.4mm)