it means that they checked the knife and everything about it twice. So it should never have any mistakes. It turned into the logo for case knives today.
It's the quality of the blade material.
do you mean numerical quantity or number of different patterns?
XX=20
XX = 20
The Case Copperlock started in 1997.
XX is the Roman numeral for 20
XX means twenty.
20
I think your are thinking of the Case RussLock knife.
The 62009 is a Case 1/2 Barlow knife.
The Roman numeral XX represents the number 20.
20. x in roman numerals is 10 so xx is 20