CastleGarden OEM Replacement Blade 305-0659
FITS MODELS: SD98, SD98 Hydro (98cm); Mulching blade 
Lenght 19 3/10'' (490mm)
Centre Hole 3/4'' (18.5mm)
Outer Holes 11/32'' (8.75m)
Centre 2 9/16'' (65mm)
Width 2 3/8'' (55mm)
Thickness 5/32'' (4mm)