Abstract: This wristlet clasp with unfolding buckle has a central portion made of two curved plates of which the relative position is adjustable and which can be secured by means of screws, the arms hingedly connected to the ends of this central portion being provided with side webs adapted to be secured by snap action to the widest element of the central portion of the clasp. The ends of the two arms to which the wristlet sections are attached and the gap possibly left between these ends in the closed clasp position are concealed by a cover plate adapted to be decorated.

Abstract: The two parts of a leather watch strap are adhesively secured to flexible metal tongues integral with a metallic body mounted in an annular groove in a watch case body, for example between a crystal and back. The flexible metal tongues are, for example, of beryllium bronze inserted and soldered in slits of the annular attaching body and the leather watch strap portions are each adhesively secured to these tongues. A metal bracelet can be soldered directly to the annular attaching body.

Abstract: This device comprises a groove (6) made in the internal wall of a through hole (2) of the case (1) giving passage to the stem (3) of the winding crown (4). A gasket (8) is placed in the groove (6). The internal diameter of the gasket (8) is less than the outside diameter of the stem (3) of the winding crown and is thus compacted between the stem (3) and the groove (6). The stem (3) is comprised by an internally screw-threaded pedestal (3') secured to the winding crown (4) and an externally screw-threaded winding stem (3") screwed into the pedestal (3'). As a result, the hole (2) can be made of relatively small diameter, which is an important advantage in an extra-thin watch whose case is of relatively soft precious metal, because the tendency to bend the case, that would be present in the case of a large hole, is overcome.