CRL Jumbo Size Plastic Horseshoe Shims are preferred for use in curtainwall construction and other installations requiring the leveling of larger members. These high-impact styrene shims are molded to a jumbo 3" x 4" (76 x 102 mm) size in standard thicknesses of 1/16", 1/8", and 1/4" (1.6, 3.2, and 6 mm). Precisely sized and balanced for vertical and horizontal installation.