Blade for Challenge 30 1/2" Diamond, standard inlaid high speed steel (AKI-IV) by Alliance Knife Company. This blade measures 36" long x 4.500" high and .438" thick, with 14 holes. (Challenge I.D. is 5-142.) When ordering knives, please double-check the brand, model and serial number of your cutter, and measure your knife carefully. There is a 15% restocking fee for returned knives due to customer error.