If you're interest is in a quality American built field sharpener that offers a broad range of sharpening angles and is the most accurate sharpener on the market, Check out the
http://edgeru.com The kit that comes with this tool will produce truly "flat" cutting bevels that are easy to maintain in the field. I carry one in my pocket at all times. There's no plastic in this tool, hand stitched WC leather sheath, anodized aluminum, with hand set and tuned tungsten carbide inserts. Adjustable in increments of 1 degree with accuracy.
We use C-2 fine grain tungsten carbide flat inserts with beveled edges to reduce drag. Hardness is RA-92 using 6% cobalt binder.
The tungsten carbide inserts used in this tool are hard enough to handle CrWear as well as CPM steels containing Vanadium carbides which are in the 82 to 84 HRC hardness range. Here is a list of the hardness of other carbide structures contained in modern knife steels.
HARDENED STEEL 60/65 HRC
CHROMIUM CARBIDES 66/68 HRC
MOLYBDENUM CARBIDES 72/77 HRC
TUNGSTEN CARBIDES 72/77 HRC
VANADIUM CARBIDES 82/84 HRC
PM me if you have questions, Fred