Review Content heated indoor/outdoor boots I put them on an hour befrore bed. Perfect Science project Used by my son in his science project, gives very good understanding of Solar PV, the energy conversion to Hydrogen for later use in Fuel Cells. Not and RC-car type of product but perfect for demonstration of sustainable and future lifestyles, very educational. great used in class as training aid Friendly Green Toy Highly sought after giveaway we use regularly. Hydrogen (water) powered build it yourself remote control car.