Compounds which are useful as potassium channel inhibitors and which because of their slow off-rates are especially useful for the treatment of cardiac arrhythmias are described. One or more walls or doors are provided with a metallic film, preferably a metallised polymeric film, capable of enhancing the performance of the refrigerator with regard to energy saving. This change of the viscosity is presented to an operator, as tactile information corresponding to the display pattern displayed as the visual information.