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 HEAVY DUTY XHT blades. Replaces the following OEM part numbers: JOHN DEERE M145516 M143520 NON MULCHERS Center Hole: 51/64" Width: 2-3/4" Thickness: .187" Length: 19" John Deere COMPACT TRACTOR: 2320 (54") ALL 54" DECKS Z445 Z435 Z425 X749 X748 X744 X740 X729 X728 X724 X720 X700 X595 X590 X585 X575 X540 X534 X530 X520 X500 X495 X485 X475 X465 X360 X340 X320 LX288 3X280 GX355 GX345 GX335 GX325 GX255 GT245 GT235 GT225 *DISCLAIMER- WE LIST BLADE PART NUMBERS, MODEL NUMBERS AND DIMENSIONS FOR REFERENCES BUT IT IS UP TO YOU TO BUY THE RIGHT BLADES. You will receive the blade that match the dimensions above.