Precision Brand 06450 - Plastic Masonry Shims
It has excellent stability, eliminates rust stained concrete, etc and also its Less expensive and more versatile than steel Convenient thicknesses, lengths and widths with assures accurate placing and leveling of precast panels, tilt-up walls, structural and architectural components. It will not rust, rot, stain or leach concrete and available in convenient thicknesses, lengths and width which permit precise leveling and alignment.