The flatness of the hammers and gongs means they can be mounted on the main plate of the movement, explaining the aperture in the dial that reveals the hammer of the repeater. This maximises the space inside the case for the calibre 1408, which shares a similar construction to that of the Chronometre Souverain, with twin barrels sitting side by side and the balance wheel just opposite.
While F.P. Journe Mens Replica says rightly that the flat hammers and gongs are louder than typical repeater, they lack the lightness and resonance of repeaters with traditional hammers and gongs. This is likely a natural limitation of the flat gongs, since they have less material to generate sound.
Pulling the thin slide on the case located at 10 o’clock winds up the small spring, which is located just under the governor, and sets the repeater in motion. While most of the repeater mechanism is hidden under the dial, with only the hammers visible when the repeater is striking, the repeater governor is on the back. Positioned just beside the balance wheel, the governor regulates the speed of the repeater strikes with a pair of wings that extend as the spring that powers the repeater unwinds. The wings encounter friction from the surrounding air as they spin, slowing the unwinding of the spring.-->