Abstract: Disclosed is a connection system for connecting together at least two ends. The system includes a casing made of an elastic structure and a sleeve passing through the casing along its axis. The casing presents a thickness that is variable and defines a sealed volume such that pressure outside the sealed volume greater than the pressure inside the sealed volume causes the resilient structure to deform elastically so as to decrease the thickness of the casing to a thickness under maximum stress.

Abstract: The device comprises a transparent tube (1) wherein may slide freely a part (4) at the extremities of which are arranged two small magnetic masses (5,6). The tube (1), closed at both ends, forms a sealed tank wherein there is placed a phase changing material (7) which is either in a liquid state or in a solid state, according to the temperature to which it has been brought. At one of the ends of the tube (1) a cap (12) containing a removable magnet (9a) is fitted. A fixed magnet (11) is placed at the other end of the tube (1). The part (4) being initially placed on the side of the cap (12), the material (7) is solidified and the removable magnet (9a) is then removed. In the case of exceeding the melting temperature of the material (7), the part (4) attracted by the magnet (11) moves towards the corresponding end of the tube (1), thus making visible a colored ring (14).