?Montres de prêt? were lent by the manufacturers to their clients to be used when their watches were in repair. These watches were often cased in stainless steel due to its durability. To our knowledge this is the first example of Ref. 1544 in stainlesssteel to appear at auction. A similar watch in "Collecting Patek Philippe Watches" by M. and O. Patrizzi Guido Mondani Editore Genova 2001 p. 168.