Oatey 50194 Rosin Core Solder 60/40, 1/2 lb, Gray 40/60 Alloy of 40% Tin and 60% Lead 60/40 Alloy of 60% Tin and 40% Lead 361 Designed for electrical-electronic work, flux residue is non-corrosive and non-conductive Can be used on wiring in stereos, motors, appliances and auto batteries 40/60 solders are 40% tin - 60% lead 60/40 solder is 60% tin - 40% lead Rosin flux is contained in the wire core; no external flux is needed