Roller Ball Tubes allow serums, fragrances or essential oils to be distributed over specific areas by rubbing the rotating ball over those sections of the body. Roller balls can be customized by the material that the ball is made from, the size of the ball as well as how many balls are needed to apply the formulation. As you can see in the images, there are single and even three ball applicators that are ideal for formulas for the face or body.