[Joe]

Yeh Una I was just about to post that

Either that or its sand cast copper. The complexity of the design would lead me to believe its cast. No one would run a mill for that long to make those small ridges in the bottom for mass mfg. I mean thats a whole lotta work for a lil pay back.

from the WBRU you can see that a cast copper block doesnt do to bad... look how Cool Computers did!