REPLACEMENT PREDATOR MULCHING BLADES MADE IN THE USA!! Not cheap imports!!! XHT (Xtreme Hardness & Toughness) blades feature a unique steel that incorporates boron, carbon, manganese, and other materials that ensure its strength. The blades are heat treated with the patented and independently tested Marbain heat-treating process. This process makes the blades 25% - 40% harder than standard lawnmower blades, making them the longest-lasting, safest, and most impact resistant lawnmower blades on the market. Predator blades provide the flat blade design preferred by most commercial mowers with an extended cutting length for increased cutting efficiency with more resistance to bending. Tighter tolerances in the aftermarket vs. OEM. By the way they are made in the USA! Hands down the ABSOLUTE best aftermarket replacement blade on the market! Replaces the following OEM part numbers: JOHN DEERE M135334 M136195 M164016 TCU30316 TCU30317 54" CUTS Center Hole: 29/32" Width: 2-1/2" Length: 19" Thickness: .197"