百達翡麗，18K白金自動上弦萬年曆腕錶，配月相、24小時及閏年顯示，型號3940G-013，約2001年製，附原廠證書、額外底蓋、轉動盒子及外包裝

Reference 3940 is the quintessential perpetual calendar and undeniably amongst Patek Philippe's greatest classics. Launched in 1984 as replacement for reference 3450, it was at the time the slimmest automatic perpetual calendar wristwatch.

The model was available in yellow, pink and white gold and platinum. All case versions but platinum were available with both solid and glazed back.