A union, similar to a coupling, allows the convenient disconnection of pipes for maintenance or fixture replacement. Although a coupling requires solvent welding, soldering or rotation (threaded couplings), a union allows easy connection and disconnection. It consists of three parts: a nut, a female end and a male end. When the female and male ends are joined, the nut seals the joint. Unions are a type of flange connector. They are available in various grades of brass and bronze and made in various sizes. They are forged for the smaller sizes and cast for the larger one. All kinds of threads can be provided as per the needs of the customer.