What is desoldering wick made of?

Desoldering braid (wick) is made of fine strands of ultra-pure copper woven and coated with flux. Its geometrically precise weave design allows for maximum capillary action and solder capacity. Soder-wick optimizes heat transfer through the braid and into the solder joint, resulting in faster wicking action than any other competitive brand. Minimal flux residue on the board speeds up the cleaning process or eliminates it entirely.