All-natural, responsibly harvested rattan makes the best diffuser reed. Ours are 3mm in diameter, for maximum flow or "wicking" of reed diffuser oil. The slightly wider reed also helps get thicker fragrances "airborne". These room diffusers come with 7 reeds to help spread the scent throughout the room. These diffusers can literally last months of fresh scented air to a small to medium sized room.