World Flow Pipes is the Best Coupling Pipe Fitting Manufacturers and Supplier in India. A pipe coupling, in the context of plumbing or piping, is a very short length of pipe or tube that has female or socket pipe threads at one or both ends, allowing two pipes or tubes of different sizes to be connected. Couplings are pipe fittings that are used to extend or terminate pipe runs. These fittings are also used to modify pipe capacity. It can also be used to repair leaking or damaged pipes.