Nox-Carb is a penetrating, high-performance sealer and stain that beautifies and protects exterior vertical concrete and masonry surfaces. Silane chemistry allows this product to penetrate into concrete's micropores, where it chemically reacts to create a bond that defies dissolution. It prevents water permeation while allowing water vapor transmission. It also protects against chloride ion intrusion and other weather-related damages. Nox-Crete Products Group. 800-669-2738.