Tantalum capacitors (or tantalum electrolytic capacitors) are solid, surface mount capacitors made of tantalum metal. They are polarized, which means they have one positive terminal and one negative terminal. The positive terminal is marked with a positive sign (+) and the negative terminal is marked with a negative sign (-). Unlike other types of capacitors, tantalum capacitors have a very high capacitance-to-volume ratio, making them ideal for tight space requirements. Tantalum capacitors are also known for their stability over a wide variety of operating temperatures, making them suitable for use in extreme conditions. In addition to their low profile, these capacitors have low leakage, long life, and low impedance, and are available in small case sizes. For these reasons, tantalum capacitors are commonly used in everything from computers and servers, to automotive applications and satellites.