Reduce your carbon footprint by keeping time with tap water. Taking its design inspiration from the moment a drop of water splashes against the ground, the Water Powered Alarm Clock keeps perfect time without batteries or electricity, you don’t even have to wind it up. Just fill the tank with straight tap water and you’re set for up to six months of accurate time keeping. Features a daily or hourly alarm and easy-to set controls. The clock converts ions in the water into clean energy power.Dimensions: 3.5"H x 4.5" diam.