Fiber sticks are custom made for use in diffusers and are less likely to clog than rattan sticks. Black fiber sticks are more densely colored than e-fiber sticks, appearing pure black even when unused/dry. These fiber sticks are strong and have a consistent color, giving the product an excellent aesthetic appearance. Each stick is 4mm thick and 250mm long. Notes: Light colored sticks can be discolored by fragrance oil, especially white sticks. Therefore, they are best used with clear oils.