Abstract: The invention relates to a heat exchanger core for use in a fluid cooling apparatus, of the type comprising two tanks (12, 13), each provided with a tube plate (17), and a number of parallel tubes (15) through which the fluid to be cooled flows and around which a cooling fluid is passed. The tubes (15) extend between the two tube plates (17). A connecting strip (20) in the form of a strengthening comb connects the tank wall (12) and the tube plate (17). The strip (20) is provided with a tube plate location slot (18) and a recess (19) adapted to house the end of the tank wall (12). The connecting strip (20) has a number of tooth-like portions or fingers (40) which extend between the tubes (15) and are bonded to the tube plate (17), but not to the tubes (15) themselves. The fingers (40) add strength to the tube plate overhang, allowing the operating pressure in the chamber inside the tank (12) to be increased without the need to use a thicker tube plate (17).