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: AYP/CRAFTSMAN 152443 163819 157033 170698 532152443 Center Hole: 5 POINT STAR Width: 2-1/4" Thickness: .187" Length: 15-1/2" These are the HEAVY DUTY long lasting blades and not mulchers! Top quality all the way! 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.