Complicated electronic assemblies and printed circuit boards require not only conformance to industry material specifications, but also alloys completely free of non-metallic oxides. The bar is rectangular in shape to differentiate from Lead-Free, which is triangular when viewed from the end of the bar. - Kester, in cooperation with the electronics industry, designed and developed Kester E-Bar. It is the answer to thorough metallic continuity, increased fluidity and reduced surface tension.