This Anvil coupling is a class 150 steel pipe fitting with female National Pipe Taper (NPT) threads on both ends to connect two male pipes going in the same direction. It has NPT threads for creating tighter seals than straight threads. This fitting is made of steel and has a black finish to provide greater rust resistance than iron and can be used for oil and gas applications. This class 150 coupling meets specifications ASTM A53 and ASME B 1.20.1 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.