Blade for Challenge 305 Diamond paper cutters, standard inlaid carbon steel (AKI-I) by Alliance Knife Company. This blade measures 35.25" long x 4.000" high and .375" thick, with 12 holes. (Challenge I.D. is 2238-4.) 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.