Very fine surgical steel wire.

Stronger than heat-stretched sprue, but only comes in natural metal,

Here you can see it in 1/72:



and 1/35:



if that matters. If you need it to be black, grey, or whatever, use stretcehd sprue.

Surgical wire is quite strong: the aerial on this Italeri 1/35 Abrams supposts, as you can see, a decal Stars and Stripes:



Don't ask about the penguin (whose name is Pivate). It's a long story...

Cheers,

Chris.