Finned tubes are elongated flat tubes that are made of aluminum cladded carbon steel and are provided with brazed aluminum fins. These tubes are used in a series in heat exchangers. The advantage they offer over ordinary tubes is that the fins offer greater contact with the liquid outside. This quickens the exchange of heat between the liquid inside the tube and the one outside it. With a normal tube, the rate of exchange of heat would be much slower.

Finned tubes are available in different shapes. They are available as oval tubes, round tubes, and flat tubes.