Gravely OEM Replacement Blade 320-535
FITS MODELS: 888015, 991006, 992009, Pro 200 and 300 series and 34Z 992056
Requires 3 for 50'' deck; rolled air-lift blade 
Length 18'' (449.3mm)
Centre Hole 5/8'' (15.9mm)
Width 2 1/2'' (50.8mm)
Thickness .250'' (6.4mm)