The Anvil locknut is a class 150 malleable iron pipe fitting with female National Pipe Taper (NPT) threads for locking two male threaded fittings or pipes for stability and reduced vibrations. The locknut has NPT threads for creating a tighter seal than straight threads and a hexagonal shape for increased leverage and use with a wrench during installation and disassembly. It is made of malleable iron, which has high tensile strength, and has a galvanized finish that resists rust in water, air, and steam applications. This class 150 fitting meets standards ASTM A-197, ASME B 1.20.1, and ASME B 16.3 for quality assurance. Class is a standard relating to tolerance, construction, dimension, and wall thickness, but it is not a direct measurement of maximum working pressure. Pipe fittings are components used for connecting, terminating, controlling flow, and changing the direction of piping in many different industries. When purchasing pipe fittings, consider the application, as this will affect material type, shape, size and required durability. Fittings are available threaded or unthreaded, in many shapes, styles, sizes, and schedules (pipe wall thickness). Anvil International provides pipe products and design services. The company, founded in 1850 and headquartered in Portsmouth, NH, meets International Organization for Standardization (ISO) 9001:2000 standards and is certified by the American Petroleum Institute (API). Its fittings meet American Society for Testing and Materials (ASTM) and American Society of Mechanical Engineers (ASME) specifications.