Plastic, for hanging. With the colored pointers of this maxima-minima thermometer, you can always keep an eye on three values simultaneously: the current temperature, the highest temperature, and the lowest temperature. You determine the observation period yourself. The display can be reset to the current temperature using the rotary knob. The thermometer is designed for indoor use and is ideal for monitoring the temperature in living spaces, greenhouses, wine cellars, or storage rooms. It is suitable for indoor use and does not require batteries.