Kester 2166-BN is a halide-free, organic flux designed for automated soldering of circuit board assemblies. This flux provides good activity on both bare copper and solder coated boards. The absence of chlorides, bromides, phosphates and highly corrosive materials facilitates removal after soldering. Kester 2166-BN provides better surface insulation resistance than typical water-soluble fluxes, making it particularly suitable for surface mount assemblies. Kester 2166-BN provides better chemical compatibility with solder resists than other water-soluble fluxes. It is free of volatile organic compounds. This eliminates the use of ozone depleting chemicals and volatile organic compounds contained in the flux removal solvents. Kester 2166-BN flux produces bright, shiny solder joints and the residue after soldering is effectively removed in standard water cleaning systems.