SIL-ACT^® ATS-42A is a clear, Low VOC, penetrating silane treatment which can be applied to the surface by low-pressure spray, brush, roller or squeegee. SIL-ACT^® ATS-42A chemically bonds with the substrate forming a penetrated layer below the surface that acts as a one way filter. Water, chloride and other waterborne contaminants are repelled without restricting the substrates natural vapor permeability.