ARÖMA - concrete essential oil diffuser | wooden box | concrete ornament | cement interior decoration | concrete diffuser. Dimensions: 14 cm x 14 cm x 5 cm (height). Take note: this set does not include the essential oil. Note: Because all the pieces are handmade and because of the nature of concrete, no two pieces are exactly the same. Each piece has slight variations (i.e. air bubbles and color). No concrete casting is 100% free of bubbles/blemishes, but that adds to its charm and character! Materials: water, non-toxic pigment, concrete.