XHT blades are made from the highest grade of steel for the best cutting and performance money can buy. With the best hardness, strength, and durability in the market, this range of blades is recommended for every mower in the market. They are stronger, harder, and last longer in any environment. Replaces the following OEM part numbers: JOHN DEERE GY20852 GX21784 3 BLADES FOR 48" CUT Center Hole: 7 LOBE Width: 2-1/2" Length: 17" XHT BLADES Extreme Hardness Toughness MADE IN THE USA!! Not cheap imports!!! Increased hardness (between 48-52 on the Rockwell Hardness Scale), without brittleness Greater yield strength—the strongest mower blades on the market Better impact toughness (ANSI-S483 compliant) Increased resistance to bending Higher wear resistance Reduced weight Faster start/stop Less wear on PTO clutch break Lower fuel consumption Last longer and need to be sharpened less frequently Our patented MARBAIN material is a durable, cost-effective alternative to abrasion resistant steel and other manufacturing materials