SET OF 6 - SUNBELT BLADE-MOWER, 17", 5/8", HL - B1DC1505 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. (3) blades for 50" cut. Fits ZTR models. Center Hole: 5/8" Length: 17" Thickness: .250 Type: High Lift Width: 3" This is an Aftermarket part. Thanks for looking!