SIL-ACT® ATS-190 FD is a clear, penetrating silane treatment which causes concrete, masonry and natural stone structures to become repellent to water, chloride, ions and waterborne contaminants, preventing their premature deterioration.  SIL-ACT® ATS190 FD forms a chemical bond which will last until the penetrated depth is abraded away. While the surface of the substrate is water repellent, it remains permeable, allowing harmful water vapor in the substrate to escape. This is the difference between SIL-ACT® and film forming water proofing products.