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. PLEASE CHECK CENTER HOLE SIZE! Set of 3 Replacement blades that replaces Kubota K5619-34330 on models ZD221 ZG227 with 54". This blade has the 7/8" center hole. PLEASE MAKE SURE YOU HAVE THE SAME SIZE. Kubota offers different hole sizes.