This knife is one of Rockstead's flagship sheath knives. The shape of the blade is dual convex . The technologically advanced process and materials used in the production of this blade, prohibits others from creating anything similar and we have confidene in our blades surface. When pushed with force, this knife will cut through a phone book as if it were better. Please confirm the improved sharpness of our evolved dual convex blade. The handle of our UN-ZDP is removable, allowing for the new handle types that we produce to be interchangd. ZDP189 is a powder stanless steel developed through the use of nanotechnology specifically for cutting implements. The sharpness of this ZDP189 blade was not really affected after cutting through hard manila rope 780 times. However, this knife is not well suited to chopping. This knife is three-quarter tang, with the option of choosing the color of the silk cord on the handle from among 4 colors : Kincya, Uguisu, Tetsukon and Azuki.