 To comply with EU RoHS and WEEE directives, we only use RoHS solders and materials. &amp;nbsp;However, not all RoHS solders are created equal. &amp;nbsp;Because some of our kitters have young children, I've chosen an antimony free solder. &amp;nbsp;This is a 3% silver bearing RoHS solder - more expensive to start for sure, but a bar goes a long way. 