Kester's solid wire for refill of solder pots that require maximum reliability of solder joints, especially for through-hole and component assembly, only solder of the highest purity is acceptable. Kester does not make any vague claims of understanding solder purity. Only the highest virgin metals are used to make Kester Solder Wire. Complete analyses of Kester Solder Wire prove that every bath conforms to the strictest quality controls in the solder industry.