XHT 16-5/8" Mower Blade (Single) - B1KU1026,1 XHT (Xtreme Hardness & Toughness) blades feature a unique steel that incorporates boron, carbon, manganese, and other materials that ensure its strength. The blades are heat treated with the patented and independently tested Marbain heat-treating process. This process makes the blades 25% - 40% harder than standard lawnmower blades, making them the longest-lasting, safest, and most impact resistant lawnmower blades on the market. Type High Lift Crossed From: A-K5576-34350 KUBOTA K557634350KUBOTA SW11945 A & I MEGA-CROSS 14096 ROTARY 92-124 OREGON 92124 OREGON This is an aftermarket product, not an OEM. Thanks for looking!