Silicone, acrylic, micronized water-based primer. Offers excellent bonding, high penetration, as well as durability to alkaline surfaces. It protects against rising moisture and salt stains and stabilizes weak substrates. Recommended for use on new or old external porous surfaces that are to be covered with paints or renders. Thinning: Up to 50% with clean water. For highly absorbent substrates, use it undiluted.