A&I XHT 14-13/16", 5/8" Mower Blade (Single) - B1GR2004,1 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. Center Hole .625" Length 14.8125" Replaces Ariens / Gravely: 3971900 Thickness .187" Type High Lift - Notched Width 2.250" Crossed From: 04265400 ARIENS / GRAVELY 14540 ROTARY 4265400 ARIENS / GRAVELY This is an aftermarket product, not an OEM. A physical address must be provided, NO P.O. BOXES. Thanks for looking!