I think you mean the somewhat more limited "... used in eastern Mediterranean Bronze Age tools ..." In the video linked to by dpeck, Cline talks about Afghanis

I think you mean the somewhat more limited "... used in eastern Mediterranean Bronze Age tools ..." In the video linked to by dpeck, Cline talks about Afghanistan as a tin source at https://youtu.be/hyry8mgXiTk?t=878 https://youtu.be/hyry8mgXiTk?t=878 . He mentions Cornwall and Turkey as two other sources, with "the vast majority" coming from Afghanistan. Cornwall provided a lot of the tin for Europe. A clue that Cline is talking about a regional supply is that he mentioned Cyprus as the source for copper, when NW Europe had other sources, like Great Orme in Wales.