Brass Compression Fittings are used in plumbing, copper tube fittings (Ferrule fitting), to join two tubes or thin-walled pipes together. In instance where two pipes made of dissimilar materials are to be joined (most commonly PVC and copper), the fittings will be made of one or more compatible materials appropriate for the connection. Compression fittings are also used extensively for hot and cold-water faucets (taps) also, the fittings allow easy disconnection and reconnection. They are used due to their ability to provide leak-tight seals. These fittings can be remade.

Compression fittings are popular because they do not require soldering, so they are comparatively quick and easy to use. They require no special tools or skills to operate. They work at higher pressures and with toxic gases. Compression fittings are especially useful in installations that may require occasional disassembly or partial removal for maintenance etc., since these joints can be broken and remade without affecting the integrity of the joint. They are also used in situations where a heat source, in particular a soldering torch, is prohibited, or where it is difficult to remove remains of water from inside the pipe which prevent the pipe heating up to allow soldering.