This waterproof concrete is hand cast in small batches and reinforced with steel for extra strength. Each piece is hand-sanded and finished with additional waterproof sealer. Copper, silver, or gold leaf pigment is applied for a minimal and contemporary look. Each piece of concrete is truly unique with its own unpredictable pattern and bubbles. The contrast between rough concrete and polished metallic finish is especially nice. They are a perfect gift and lovely for all ages.