This eco-friendly calculator is powered by water. This eco-friendly calculator has an in-built water battery - just add water and within a few seconds you will be ready to calculate. Power can be restored repeatedly by topping up with plain water.
This eco-friendly clock is powered by water, and has four functions: Time, Temperature, Countdown Timer, and Alarm. The H20 Multi-Function Clock incorporates a revolutionary patented water-powered battery -- just top it up with regular tap water and see it spring to life!