Abstract: A vacuum-closed cap provided with a device to open containers completely designed to allow the release of the inner pressure of the container (2) so that it can be opened later on, said cap (1) being fully removed therefrom and being comprised of a gripping ring (3), attached through its front tab (4) to a shoulder (5) on its surface (6), said shoulder (5) being provided with a slit (7) in the junction between same and the surface (6) of the cap (1), in such a way that, when the tab (3) is manually pressed vertically upward, it reveals an orifice (8) caused by the disruption of said slit (9), said cap (1) being provided with shoulders or claws (9) which, during the filling process, are coupled to the packing wire (2) or the lip (10) thereof, thus attaining a perfect coupling between both the container (2) and the cap (1).