I would probably buy those X ht's from you for my FasTrak but I already have a set under there! I can't hardly even make those blades dull even if I try.... although I don't let rocks go through there. My blades will probably still be under there in 8 or 10 years when I trade the mower off for a newer one! They are an awesome blade for sure as somebody's getting a heck of a buy here if they pick them up!