Oregon 98-634 MTD and Troy-Bilt Gator Mulcher G3 Replacement Lawn Mower Blade 16-1/4 in 16-1/4" Length, 5/8" 6 pt. star Center, 2.5" Width, 0.187" Thickness, 1" Lift Replaces MTD and Troy-Bilt #742-0644, 942-0644 For MTD and Toro - (2) 98-634 and (1) 98-670 needed for 46" Cut, The 98-634 are the two outside blades needed for 600 and 800 series decks (1997 and beyond), and order 1 of 98-670 for the center blade MTD built blades Bolens, Cub Cadet, Troy-Bilt, White, Yard Machine, and Yardman mowers may have a 6 point star center hole. This Oregon replacement blade will have a "Y" shaped center hole which will fit exactly on the 6 point star on the blade spindle. Blade may come with a Y or 6-point star center hole. Both will work for the applications mentioned