Mtd OEM Replacement Blade 335-711
Requires 2 for 42'' deck; mulching blade 
Length 21 3/16'' (538.2mm)
Centre Hole 6 pt. star 
Outer Hole 5/16'' (7.9mm)
Centre Hole 2 1/2'' (63.5mm)
Width 3'' (76.2mm)
Thickness .149'' (3.8mm)