The present invention relates to a pressure equaliser (1) comprising: - a hollow element (101) with a cup-shaped section (1011) and a tubular section (1013) that merge seamlessly one into the other, and - a sealing element (103) that comprises a top edge (1031) with a first diameter (D1) and a central part (1033) with a second diameter (D2), wherein the top edge of the cup-shaped section (1011) of the hollow element (101) is inserted into the second inner diameter (D2) of the central part (1033) of the sealing element (103), the pressure equaliser being characterised in that at least the hollow element (101) can be disassembled into at least two hollow element parts (10a, 101b) along its longitudinal axis. The present invention further relates to a baby bottle assembly comprising: - a bottle-shaped container (3), - a pressure equaliser (1) according to the invention, - a screw element (5) and - a nipple (7a) or closure cap (7b).
