XHT BLADES Extreme Hardness Toughness MADE IN THE USA! Don't be fooled by other cheap imported blades you see on eBay! Buy from home! The XHT blades are made with MARBAIN which is what makes them THE BEST BLADE ON THE MARKET! Increased hardness (between 48-52 on the Rockwell Hardness Scale), without brittleness Greater yield strengthÂthe strongest mower blades on the market Better impact toughness (ANSI-S483 compliant) Increased resistance to bending Higher wear resistance Reduced weight Faster start/stop Less wear on PTO clutch break Lower fuel consumption Last longer and need to be sharpened less frequently Our patented MARBAIN material is a durable, cost-effective alternative to abrasion resistant steel and other manufacturing materials This sale is for 3 replacement XHT blades. Replaces the following OEM part numbers: CRAFTSMAN/HUSQVARNA/POULAN 173920 180054 5321800-54 5321739-20 917173920 539107519 3 Needed for 48" cut machines Center Hole: 5 POINT STAR Width: 2-1/2" Thickness: .204" Length: 16-3/4" Â· Disclaimer: We list model numbers and part numbers for references only. At times the same model may take different parts based on serial number breaks or manufacturers specifications. We list all the specifications on the part (size, width, length, thickness, etc.) and YOU must know what is needed on YOUR application. We canÂt possibly make it more known as to what you are receiving when you purchase.