I did a search and came up with a little info about the steel used in the Delta-Z line. Evidently, some knives use the German 1.4116 steel, which you say is a near equivalent to 440C. Your liner locks use the German equivalent to 440A. I guess your tactical series uses Sandvik 12C27. My question is: how many different types of steel do you use? What can you tell us about these steels? Who does your heat treating? At what Rc do you harden these different steels? I wish there was more info about the steels used on your knives on your website! I thought it was sort of unusal not to include some steel info (other than the vague term "stainless") on your site for knives in this price range. Your knives are really quite nice, I look forward to learning more about them and eventually picking up a couple. Thanks!