The 657 range of instrument watches is based on the 656 line the 657 s is an all black timepiece that focuses on instant readability it is equipped with eta 2824 2 automatic calibre that performs 28 800 vibrations per hour and has 25 bearing jewels the extreme protection from magnetic fields is one of the most prominent characteristics of this model additional features include a captive pilots bezel that measures elapsed time a date window located between 4 and 5 oclock luminous dial ele