CV or "Chrome Vanadium" is modified 1095 carbon steel, it will rust, if not cared for, but is usually considered to be the better steel from Case, easy to sharpen and holds a much better edge than Case's SS "Stainless Steel" which is 420hc. Case's 420hc is not all that bad, but their heat treating could be better IMO.
Also, while CV will rust, it does not rust quite as fast plain high carbon steel, wipe it off after use and re-oil occasionally and it will develop a nive dark "patina" that looks nice and helps prevent rust.
I don't really dislike Case's SS, but will always choose their CV when I can.