Hi Alan,
I believe they are silver Eichmanns, but I'd have to get some help to confirm that.
The copper cables I have are not KCI, but Chimera labs advantage II and they are just a bit more transparent in the mids and highs with the silkworms being ever so slightly warmer but still detailed, dynamic and very full sounding.
On other speakers I have had, the silkworms added that little bit of warmth they needed. Of course this is my system, in a small room, low to medium listening levels, and single ended tube amplification.
Hope that helps,
Jim