I think I found the answer, and you and alaskanpiper are correct.
For old antiquari pipes to be sold in the USA (US), they use G and GG for the size, any for any other country they use K.
Thanks a lot !!!
Does anybody knows why some Old Antiquari Castell are K grading, an another ones not ?
Where can I get Cavicchi's estate pipes ?, been looking, but find very few.
Thanks a lot, stay safe, God bless !!!