For soldering applications that require maximum reliability of solder joints, especially for surface-mounted components, through hole and final assembly, only solder of the highest purity is acceptable. Kester does not make any vague claims of understanding solder purity. Only the highest quality metals are used to make Kester Solder Wire. A complete analysis of Kester Solder Wire proves that every batch conforms to the strictest quality controls in the solder industry.