MAC Ultimate Series uses 2.5-3.0-mm. blades with larger bolsters than our Professional Series to mimic the weight and heft of a traditional European, forged knife while maintaining a thin, Japanese style stamped blade. The blades are made with sub-zero tempered MAC Superior steel for better edge retention. The ultimate combination of high carbon steel, Chrome, Molybdenum, Vanadium, and Tungsten Carbide makes the blade harder and more durable than most other brands. Made in Japan.