Liquid Calculator also available with battery back-up These unique liquid powered digital clocks are very environmentally friendly.  Using fuel cell technology, these digital clocks use hydroelectric power to run and no batteries ! Models derive power from electrolytic fluids such as water, fruit juice, soft drinks, beer and coffee.  Fuel cells at the back of the clock use the fluids which are converted into energy, eliminating the use for regular batteries. Four different styles available, all clocks display the hour, minute, second, date and month. So you can have a water powered digital clock, a fruit juice powered digital clock, a beer powered digital clock, a soft drink powered digital clock or a coffee powered digital clock.                                       Model 3206                                               Model 3207                                                                   Model 3208