I looked at the ones listed in the Smokey Mountain Knifeworks fall catalog, and when they list the steel at all(except as "stainless") they say it's "400 series" stainless. Old trick the factories use, i.e. when they list a blade as "440 series" steels, they almost always mean 440A instead of the higher quality 440C. I mean, if they were using 440C you could bet your boots they would surely say so. In this case, I suspect "400 series" means 420 stainless, which is the bottom of the barrel as far as stainless goes in knives. Can't think of any other 400 series out there, now that 425M(Bucks old steel) doesn't seem to be around anymore.