XHT BLADES Extreme Hardness Toughness 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. By the way they are made in the USA! Hands down the ABSOLUTE best aftermarket replacement blade on the market! This sale is for 2 replacement XHT blades. Replaces the following OEM part numbers: JOHN DEERE GX20249 GY20567 Blade specs Center hole: 11/16" Outside holes: 13/32" Center to Center on outside holes: 3-3/4" Width: 2-1/2" Thickness: .187" Length: 21-3/8" COMMERCIAL PREDATOR BLADES DISCLAIMER: Please make sure you are ordering the correct blades. We list model numbers, part number and the exact dimensions so you know exactly what you are getting. The same model number normally has different deck size options. You may have an (XYZ) model but it may have a 48", 54", 60", etc. deck size. The same blade will not fit all of them, of course. You will RECEIVE the blade to match the dimensions above.