Replacement XHT Lawnmower blade. XHT(Xtreme Hardness & Toughness) blades are 25-40% harder than standard lawnmower blades. Benefits of the HXT blade are sharper and longer lasting cutting edges.More Resistance to bending. Tighter tolerances in the aftermarket vs. OEM. XHT blades also offer greater impact toughness. (1) B1WA3400 and (1) B1WA3401 for 42" cut. (3) blades for 54" cut.Grass handling system. Rear discharge. Right hand cut. OEM Cross Reference 3446 355-024 5705-3 91-913 Fits models:Walker : SEVERAL (42" & 54")