Quikrete® Mortar Repair is a water- resistant acrylic formula that remains relatively flexible. It is textured and colored to give the appearance of masonry mortar. The product has minimal shrinkage, excellent adhesion and is non-flammable. The unique square opening is ideal for filling 3/8 Inch mortar joints. It is a sanded acrylic formula that adheres to brick, block, stone and concrete surfaces. Texture and color blends with the surrounding mortar. The square applicator tip is designed to smooth mortar joints.