This plastic thermometer with a white frame is weatherproof and can be used indoors or outdoors. By controlling the indoor temperature, you save heating costs ? up to 6 % with a one-degree temperature reduction. And simply feel more comfortable. When installed outdoors, the outdoor temperature provides you with important information for home, garden, leisure and work. The capillaries are filled with a specially colored thermometer liquid. Mercury has not been used for this for a long time.