KEY POLYMERIC BLOCK FILLER is an acrylic-based concrete block filler. Consisting of a specially formulated blend of acrylic polymer, cement, and fine silica, Key Polymeric Block Filler is easy to mix and apply. Key Polymeric Block Filler provides a pinhole-free filling for interior and exterior masonry surfaces. A "stiff mix" of Key Polymeric Block Filler can be used to patch holes and cracks. Non-powdering, Key Polymeric Block Filler is ideal beneath Key Epoxy Wall Coatings.