Good quality soldering wire - Flows well and heats evenly, easy to use. Good soldering ability in both electrical conductivity and thermal conductivity; with the soldering wire spool, soldering is done quickly. Rosin core solder - Our solder contains 2% rosin, rosin is uniform and suitable, no flux required, insulation resistance, no splashing and non-corrosive. Good melting point - 215 - 220. degrees Celsius / 419 - 428 degrees Fahrenheit °, can be used for most soldering irons.