The Cylinder flowerpots set of 2 from Broste Copenhagen are crafted from fibre clay and are suitable for indoors and outdoor. Fibre clay is a light weight material. Wipe the surface with a damp cloth after removing from the carton to remove salts. Due to the nature of the fibre clay production process colour variations are to be expected. If using outside it is recommended, by Broste, to drill a hole in the bottom of the pot.