The inner, thicker ring signals the hour, and the outer, thinner ring the minute, according to the standard positioning of numbers around a watch or clock face. In the image to the right, for example, the watch is indicating a time of 10:10. The Ziiiro Mercury is the higher-end version, available in fewer color schemes than the Gravity but featuring a stronger, stainless-steel wrist band. The Mercury's pop-out face and interchangeable colored rings allows buyers to experiment with multiple color configurations.