Requiring no electricity to operate or concrete/block/lumber pad to install, the Thermosink Energy-Free Livestock Waterer consists of 8.5" insulated tanks (a main tank and one or two bowl tanks, depending on the model) that have been sunk vertically into the ground, with about 20 inches showing above ground. Hooked up to the main tank is a flexible-hose water supply line, which is designed not to freeze if properly installed and maintained. The water is either pumped or gravity-fed to the main tank that has a water-level float, and then flows into the bowl tank from which the animals drink. Self-circulation keeps the water fresh; when not needed, the system can be turned off with an external shutoff. The single-bowl unit accommodates up to 200 head on pasture or in confinement; the double-bowl unit waters well over that number and can be set up with one bowl on each side of a pasture-dividing fence.