24-6337-6401 is a water soluble, 3.3%/331 flux-cored wire with Sn63Pb37 as its alloy material. It has 0.50mm (0.020in) diameter and weighs 1lb per spool. This cored solder version of the popular 2331-ZX Neutral Organic Water Soluble Liquid Flux is more effective than rosin fluxes in soldering difficult metals. The flux is more heat stable than most organic fluxes, resulting in minimal smoke and odor. The residue can be completely removed with a simple heated water rinse. Deionized water is suggested to prevent introduction of chemistries from unknown water sources.