The watch in question is a 1996 Patek Philippe Grand Complications Perpetual Calendar ref. 3970EP in Platinum. The watch features a manual-wind Caliber 27-70 (Lemania ébauche) movement, a 36mm platinum case, pointed baton hands, a chronograph, diamond hour markers, 24-hour indicator, twin date/month apertures, a moon phase, and leap year indicator.