One pack - 20m - of bare copper wire, 0.4mm.
This fine wire is great for making your own coils for ganutell and cartouchage work.
This is one of the standard sizes used in the Ganutell Country Flowers handbook.
It can also be used when creating wired skirts and ruffs.
This size can be threaded through the 1.90mm perl wire to strengthen shapes made with it.
0.4mm = @27 SWG (standard wire gauge)