A grooming tool which includes a number of latex surgical tubing pieces generally arranged in parallel to one another, and anchored together at corresponding opposite ends. In particular, the present invention pertains to the use of probiotic micro-organisms for balancing the skin’s immune function under stress conditions, such as a exposure to ultraviolet radiation, specifically for enhancing the skin’s immune activity and reducing the tendency to develop allergic reactions under such conditions. In some embodiments, at least one of the beam paths, has an optical element, which is implemented having an optically transparent, deformable volume body, and which has at least one interface toward a medium having an optical index of refraction deviating from the volume body.