Brass contains copper and zinc and is often combined with other metals to produce material that resists corrosion and conducts heat and electricity. Brass sheets and plates are solid, flat pieces of metal that come in different sizes and material grades and are often manufactured into fasteners, gears, and brackets. Brass bars have rectangular or square cross sections and come in different materials grades for specific applications. Brass rods are solid lengths of metal available in different material grades that make them easy to form and machine. Brass tubes are round or rectangular with a hollow center and are lighter than solid rods. They are commonly used for structural applications. Brass angles are available in different sizes and material grades and provide support in industrial and architectural applications. Brass ball stock is often used in ball valves due to its low-friction properties and ability to withstand exposure to water, gas, and oil.