According to Botta Design, “The UNO 24 one-hand watch gives the wearer the chance to approach time in a completely new and far more conscious manner. It presents the entire day at a glance. During the course of each 24-hour period, the single hand of the UNO 24 completes just one full rotation. The watch’s special scale means that each time of day is indicated by an individual position of the precise hand. Even a fleeting glance is sufficient to show the wearer instantly and clearly how far the day has already advanced.”
The meridian is divided by a color shift on each watch so determining day from night is quite easy. Granted, you could always look and see it is is dark outside.
In other words, the positioning of the watch hand on the dial corresponds to the position of the sun in the sky. The precise scaling means that the time of day is shown with an accuracy of around five minutes claims Botta Design.
Available from Botta Design.