Excellent quality general purpose solder Acid Core Solder has a highly active flux for common metals For use on highly oxidized and difficult to solder metals Residue is corrosive and must be washed with hot water. Works with Stainless Steel Contains: 96.5%Sn / 3.45%Cu / 1%Sb / 0.05%Ag and Melts at 419-428 Degrees F (215-220 Degrees C)