BYK 3455 is a polyether-modified polydimethylsiloxane additive that improves substrate wetting and leveling in aqueous systems and solvent-free UV coatings. BYK 3455 greatly reduces surface tension, resulting in significant substrate wetting and leveling improvements. Difficult substrates like wood with porous and uneven surfaces can be effectively wetted. BYK 3455 does not stabilize foam or negatively impact recoatability. Coating defects such as picture framing and fish eyes are considerably reduced. As a highly compatible additive for various binder systems, even with low co-solvent proportions, BYK 3455 is ideally suited for modern coating formulations. Using BYK 3455 in coatings can deliver benefits such as reduced static and dynamic surface tension for better substrate coverage. It also enables difficult porous substrates to be effectively coated with minimal defects.