Murry OEM Replacement Blade 335-764
FITS MODELS: 42170X9A 
Requires 2 for 42'' deck; hi-lift blade 
Lenght 21 1/4'' (539.8mm)
Centre Hole 7/8'' (22.2mm)
Width 2 1/4'' (57.2mm)
Thickness .134'' (3.4mm)