Dometic A1625 Vent W/T-Piece (4 Piece Kit).

The bottom grill lets fresh cool air in, while the top vent has??2 outlet sections. The small section to the right takes the exhaust gases/heat directly outside and the larger section takes the warmed up air that flows past the fridge fins to the outside. Both cut-out holes should be 451 mm wide and 156 mm high.