Featuring a chemistry of 99.3% tin and 0.7% copper, this lead-free solder alleviates concerns about the effects of lead on the body and on the environment. Ideal for general purpose soldering including PC board repair and tinning wires. Rosin in the solder core melts before the solder and chemically cleans the surfaces for a more reliable solder joint. > 1mm diameter is suited for most soldering tasks. 1 pound roll is a generous amount for the avid electronics enthusiast or electronics professional.