Abstract: Pocket watch comprising a middle, a movement accommodated in the middle, a crystal, a cover for protecting the crystal, a stem for setting the time of the movement, and a device for locking the cover. The locking device can be released by manipulating the stem to open the cover. A water-tight enclosure enables the movement to be accommodated and protected. The water-tight enclosure encloses the middle. The locking device is outside the water-tight enclosure. The stem passes through the water-tight enclosure through an aperture and a water-tight joint provided in the aperture. The water-tight enclosure includes a casing ring accommodated inside the watch-case.