The invention relates to a cap designed to be coupled to the neck of a container. The cap comprises an inner body (1) and an outer body (2, 2’) coupled around the inner body (1), the rotation of the outer body (2, 2’) causing same to move in an axial direction with respect to the inner body (1). The inner body (1) comprises a peripheral skirt (7) having a lower part split into a plurality of feet (8). The feet (8) comprise outer surfaces that form a frustoconical shape with a sloped generatrix (10) converging upwards, and inner surfaces with projections (11) that delimit a circular hollow. The cap also comprises a sealing device (14) for preventing the rotation of the outer body (2) with respect to the inner body (1).