Hi All:
Came across some single nylon strings, presumably for guitar, but maybe not. The little envelopes that the strings are in say this:
6th D=Bb
4th B=G#
3rd E=C#
2nd X=F

Obviously, I'm missing some, and I don't have the outer package that the whole set came in, which might have had a brand name or more clues. They are tie-end (no ball), and the string in the envelope marked "4th" is a plain (not wound) string. (Could have been put in the wrong envelope?) These could be from Israel(??), as they were in a case with a guitar that appears to be Israeli made. Then again, text is English, so could be UK, US, or pretty much any origin.
Anyone know about these strange designations? I'm super curious and perplexed. Thanks in advance!
~CC