Iron Rock Stone Sealer and Impregnator molecular structure physically impregnates the porous surface of stone and as it cures it EXPANDS to fill the pores. Traditional silicone based sealers or impregnator products have a higher surface tension (larger molecules) and therefore do not physically "fill" all pores (see above picture). As a result, the molecular structure wants to "ball-up" and not completely fill the pore. Stone whose surface pores are not fully sealed are susceptible to stains from oil, water, and acids. Only Iron Rock Stone Sealer fluoropolymer technology can completely fill these pores whereas silicone based products cannot.