Abstract: A tamper-evident device for application to a container closure cap has a ring element which surrounds an insert panel element. The insert panel element, which is centrally disposed with respect to the ring element, has an edge displaced from and surrounded by an edge of the ring element and is connected to the ring element by at least two lugs. The ring element of the device is bonded to an outer surface of a container closure cap which has a centrally positioned portion which is elastically deformable under the effects of changes in pressure so that when positioned on a rigid container which has an interior under a partial vacuum and upon opening and pressurization of the container, the deformable membrane lifts the insert panel element to break lugs connecting the ring and insert elements.