A wet cell is a galvanic electrochemical cell with a liquid electrolyte. Wet cells are a precursor to dry cells and are commonly used as a learning tool for electrochemistry. It is often built with common laboratory supplies, like beakers, for demonstrations of how electrochemical cells work. A particular type of wet cell known as a concentration cell is important in understanding corrosion. Car batteries are wet cells and give a good example of the pros and cons of such systems. The most famous wet cell is the Daniel cell, which is sometimes referred to as a crowfoot or gravity cell. In the Daniel cell, copper and zinc electrodes are immersed in a solution of copper (II) sulfate and zinc sulfate respectively.