Kester 979VT is a VOC-free, no-clean flux formulation for high quality, low-defect soldering of lead-free electronic circuit board assemblies. - This Kester flux has a finely tuned activation system which offers the best wetting available in VOC-free liquid flux technology and the shiniest solder joints. 979VT also reduces micro-solderballing on glossy and matte laminates and between connector pins. 979VT will not attack properly cured solder masks or FR-4 Epoxy-Glass laminate. It has been specially formulated to accommodate needs of single sided board assemblers. 979VT leaves no haze or visible residue behind, including the white powdery residue associated with use of earlier no-clean formulas. The miniscule amount of non-visible residue that remains after soldering is non-conductive, non-corrosive, and does not need to be removed.