Clay brick : Acid-resistance,Alkali-resistance,no penetration,fast vaporized,no elga existing Clay brick color: Red,Reddish Brown, Brown, Bisque yellow, brown, grey etc. ... :about 6% moistureproof and anti-penetration,anti-slip Feasure: Acid-resistance,Alkali-resistance,no penetration,fast vaporized,no elga existing (completely oxidated)and ...