ThermoFlow Solder Wire (Rosin-Core) - 63/37 - 1/2lb Roll - 0.6mm Dia. 63/47 Ratio - 0.6 mm Diameter - MC20A Flux Type - 2% Flux Meets RoHS directives when combined with a lead free alloy. Rosin based flux that is suitable for Lead Free and Tin- Lead based solder Suitable for temperatures ranges of 572-752 degrees Fahrenheit Order is for 1 Roll / 1/2 Pound per Roll