Silanes are one of the impregnators manufactured by HMK Stone Care Germany. The silane molecule is the smallest of the solvents for carrying water repellants deep into stone. For more information, please see article from Dow Corning.
Because of these unique properties, silane based impregnators offer better protection for dense granites, usually darker colored granites, for concrete, and cultured stone. The smaller molecule allow the deepest penetration of protective elements, thus offering superior water repellence.
HMK S31 is the world standard for dense stone and concrete protection.