The 44-6337-0030 is leaded bar solder manufactured by a special process that controls the inclusions of oxides and metallic and non-metallic impurities, Kester Ultrapure® is the industry standard bar solder for use in high tech electronic applications where lower surface tension and hole filling ability are essential. The purity of Ultrapure meets the requirements of IPC/J-STD-006C and will conform to these requirements when purchased directly or through stocking distributors.