Abstract: The invention relates to a plate (20) for a heat transfer tube (4) made from a metal sheet comprising a peripheral outer wall (10) and having at least one first cavity (24) and least one second cavity (26) respectively formed in the metal sheet. The first cavity (24) is in contact with the peripheral outer wall (10) and that the second cavity (26) is arranged at a distance from the outer wall (10). The invention also relates a heat transfer tube (4) of a heat exchanger (1) including a pair of such plates (20) and a heat exchanger (1) including a plurality of such tubes (4).