Plastic, for hanging, with the colored needles of this maximum/minimum thermometer you always have three values in view at the same time: the current temperature, the maximum temperature and the minimum temperature, you determine the observation period yourself, the display is reset to the current temperature is reset, the thermometer is designed for indoor use and is therefore ideal for checking the temperature of living spaces, the greenhouse, in the wine cellar or in storage rooms, suitable for indoor use, does not require batteries