The original thermometer..yes, THAT Galileo invented this strikingly beautiful instrument, using the fact that as temperature changes, liquids with different densities rise or sink. So 5 balls of different weights and colours, each tagged with a temperature float in the liquid in a glass container, and the lowest floating one tells you the current temperature (within 2 degrees). Set for indoor comfort temperatures,18C to 26C, in 2-degree increments. Home or office uses - often the talk of the office! Firmly-packed but glass is fragile, so set up in a sheltered location. . Comes in 2 sizes - the displayed is one is the smaller, 28cm tall. There's also a taller version (44cm tall) at $64.90 German made.