Rectorseal 14820 8-Ounce Nokorode Hot Weather Paste Flux-Tool Cleans and fluxes in one operation saving time and money Hot Weather Flux works to deliver a strong, leak-free joint It's non-aggressive formula is ideal when used on copper and brass fittings Lead free and acid free-safe to use on potable water systems When heated, it reduces surface tension and allows the solder to flow easily and uniformly into the joint