BYK W 903 is a wetting and dispersing additive that facilitates and improves the incorporation of inorganic fillers into ambient-curing epoxide and polyurethane systems. BYK W 903 reduces viscosity particularly if the filler content is high and the resin-filler mixture becomes more homogeneous. BYK W 903 additive allows for easier processing and application of filled formulations. It ensures a well dispersed, homogeneous mixture leading to improved performance properties like strength and durability in end use applications.