Oregon 596-719 Gator G5 Blade, 18-15/16" Center hole: 13/16" Tungsten carbide is fused into the blade  creating an ultra-hard layer at the cutting edge and increasing the time between sharpening Gator Mulcher provides cleaner, more efficient cutting performance can eliminate the need to bag, saving time and hassle. X-Tended Cutting Length optimizes the cutting efficiency with each revolution The aggressive blade angle increases air flow to push debris up-and-out for superior bagging or side discharge. Replacement for major brand: John Deere