PATEK PHILIPPE NAUTILUS REF. 3900/1, 80S Two body brushed and polished stainless steel case, n. 1815527. Nautilus steel bracelet with deployant clasp. 
Anthracite dial with horizontally ribbed decoration, signed, Swiss indication flanked by "Goute à prior”, applied bâton indexes, minute/second division, aperture for the date. Luminous white gold bâton hands, centered seconds. 
Signed quartz movement, rhodium-plated with Calatrava pattern caliber E23-SC, n. 1550638, 7 jewels.
Diameter Ø: 32 mm
Note: working.