Plant holder SANDSTONE D40xH56,5cm, brown polystone. The plant holder is made of a composite material, which is a mixture of natural stone powder, fiberglass, sand and polymers. In appearance like natural sandstone, polystone is lightweight and weather resistant. The base frame of the flower box is made of acacia wood. SANDSTONE series is suitable for both indoor and outdoor use. We recommend not to leave the flower box outside for the winter. If the plant holder stays out for the winter time, it must be empty and placed upside down.