Abstract: A composite capsule and variants thereof for closing and sealing bottles and similar containers, which is essentially composed of two elements: a rigid capsule (2) and an extensible plastic diaphragm (2), integral therewith. Various processes for making the composite capsule and variants thereof. Said composite capsule and the variants thereof may be fitted in a single step on to bottles (1) and similar containers, by using conventional sealing apparatus. The capsule may also have an axial extension in the shape of a drinking-glass (30) whose specific function is supplemented by a tamperproof seal function.