Sorry for the late reply, been busy moving, again. You will like it very much.
Ruanas were always the answer to sportsmen who had a Case or Union Cutlery or Marbles, etc break or come apart in the field, or have stacked leather get all shrunken, and pommel/guard get all rattley. The knives very much the same base design, but with Rudy's flair, strengthened, and handle attached which would never shed a pinned pommel, etc.
The 21A is the answer to all those who have admired the straight classic American field knife as still mass produced to this day, but who always wished it were built stronger in every way. Your boyhood likely will flash before your eyes when handling it, and you will start to wonder who started that 6" knife silliness when this knife can clearly do anything a 6" can do, and it a heck of a lot easier to wear.
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Cadent a latere tuo mille, et decem millia a dextris tuis;
ad te autem non appropinquabit.