For optimal performance, every decorative fountain must be properly leveled. Aquascape Fountain Shims are perfect for leveling a variety of water features, including those made of resin, concrete, and GFRC. Made from durable plastic, these shims are resistant to water damage and can be stacked as needed. Each shim measures 4.5″ by ¾″, and the pack includes six easy-to-use shims.