HYT H1 watch uses a liquid-filled chamber to display the hours using a luminescent green fluid. The green stuff is fluorescein, which is used in forensics to detect latent blood stains. I suspect it would look great under a black light.
The Two bellows are powered by the watch movement, and they push and pull the liquid around the face to tell the time. The minutes are shown in the center of the watch face with a dedicated dial. The second hand is modeled on a water turbine.
HYT claims that there are seven pending patents for this watch. The price is $45,000 which is a bit extreme to tell the time. I personally use my phone to tell the time or my computer.
Watch the video below: