Stainless Steel Hex Nipple Pipe Fitting , used for industrial connection of pipes or fittings of different end types, diameters or materials. It is a component used to connect, terminate, control flow and change the direction of pipelines in many different industries. It can be applied to water, air, gas, oil, fuel, refrigeration, meters, etc. (NPT thread size is not the actual diameter, it is only the nominal pipe size)