Mono-rattrapante The "Mono-rattrapante" chronograph wristwatch, with single hand, is equipped with the device elaborated by Bovet on the Valjoux calibre 84. This particular wristwatch features the three normal functions of any single button chronograph, activated through the push-piece at 2, enabling the chronograph hand to: start - stop - return to zero. In addition, there are two further functions activated through the push-piece at 4: 1 - by depressing the push-piece, the single chronograph hand stops. 2 - by releasing the push-piece, within a maximum time of 60 seconds, the hand jumps forward, catching-up the seconds elapsed in the meantime. Two versions of this wristwatch exist: - the first, features a round, flat push-piece at 2 and an oliveshapped push-piece at 4. - the second version has either a square or a round waterproof push-piece at 2 and at 4. Similar watches are published in Chronograph Wristwatches, To Stop time, by Gerd - R. Lang and Reinhard Meis, pp. 21, 50-51, 180-181.