Airlite Hystorica Stone is an invisible, water-repellent coating specially formulated to protect natural building materials like stone, marble and various limestones such as travertine.
"Its formulation is the result of the aqueous dispersion of the water repellent photocatalytic nanoparticles of titanium dioxide. Its innovative formula gives the self-cleaning characteristic against the organic substances with which it comes into contact. The photocatalytic reaction occurs in the presence of sun-light and permits the reduction of air pollution decreasing both the concentration of NOx and Sox." - Hystoriqa Stone Technical Sheet accessed 5/16/17 (click 'Documentation' on product page for access)