Hydro Power Calculator - $13.00

Admittedly, Hydro Power is probably the wrong name for this Kikkerland designed product, it was catchy. What they are, are water activated batteries made by a kind of powdered carbon capacitor.
This process which was discovered by Japanese inventor Susumu Suzuki, requires moisture to activate the carbon particles to produce energy. They produce the same amount of energy as normal batteries, but they are made of carbon, which is everywhere, and not processed metal, which is hard to find, they are much cheaper, take less energy to produce and are non-toxic.

Price: $13.00 & FREE Super Saver Shipping on orders over $25.