Patek Philippe Perpetual Calendar Chronograph 3971

A FINE AND VERY RARE YELLOW GOLD PERPETUAL CALENDAR CHRONOGRAPH WRISTWATCH WITH REGISTER MOON-PHASES AND SNAP-ON SAPPHIRE CRYSTAL BACK DISPLAY REF 3971J FIRST SERIES MVT 875078 CASE 2824140 MADE IN 1987 yellow gold diameter 36 mm , • cal. 27-70 manual winding nickel lever movement, stamped with the seal of Geneva, 24 jewels, free-sprung Gyromax balance, adjusted to heat, cold, isochronism and 8 positions • silvered dial, applied square and baton indexes, outer minute and 1/5 seconds divisions, subsidiary dials for constant seconds combined with 24-hour indication, 30-minute register combined with leap year indication and date combined with moon-phases, twin apertures for day and month, calendar in Italian • 18k yellow gold polished case, concave bezel, stepped down-turned lugs, snap-on sapphire crystal back display • case, dial and movement signed • with an 18k yellow gold Patek Philippe buckle