DRYLOK Siloxane 7 Brick and Masonry Penetrating Sealer is a clear, durable, water-repellent, specialty formulation for use on exterior, above-grade, vertical and horizontal brick and masonry surfaces. with just one coat, it minimizes the deterioration of masonry and mortar and helps control efflorescence (salt deposits) and surface staining. DRYLOK Siloxane 7 Brick and Masonry Penetrating Sealer has no sheen and is virtually invisible on stucco, brick and concrete.