The Tau planter from the Rectangulum collection is made of fiberglass, a composite material consisting of fibreglass and synthetic resin that is lightweight yet strong. The structure of the planter has the appearance of concrete. This planter is suitable for both outdoor and indoor use. The frost resistant property ensures that the planter can remain outside during cold periods without getting damaged. In addition, the planter is UV resistant, making it protected against discolouration and damage from sunlight.