A milk collecting piece comprises a kink element having a bending edge which ensures reliable kinking and thus maintenance of the operating vacuum in milk tubes which are guided outwards in a direction oblique to the longitudinal axis. The colored layer 14 comprises reflective flakes 16 and a dye that is covalently bonded to a polymer 18. Improvement in performance is obtained by the incorporation of dynamic mode switching and forward-backward smoothing in the location position estimator. The method may also include determining a second quality of experience metric associated with the media stream at a second network node.