Alan,

This type of wire has been sold for bonsai use before but it is not truly
suitable for bonsai unless it is annealed again. It has certainly been
annealed to some degree in the manufacturing process but in winding and
unwinding from large spools to smaller lengths, the wire is bent at least
twice, probably more and each bending stiffens the wire (work hardens it)
reducing the softness that is the whole point of annealed copper for bonsai in
the first place. Wire of the sort that you have purchased is the same kind
that I buy and anneal again to achieve the proper softness for bonsai use.
Annealing is a little bit mysterious but not beyond the capabilities of most.
It is a dirty, time consuming, and sometimes dangerous business even is you
anneal thousands of pounds of it a year for bonsai use as I do.

Julian R. Adams aka the copper wire guy
Adams' Bonsai
Lynchburg, VA