Stainless steel self-winding round-shaped water-resistant gentleman's wristwatch case-back with 5 screws subsidiary seconds at 9 guilloché engine-turned and mother-of-pearl dial and five horological complications: 1/8 second chronograph (tachometer graduation on the bezel to 400 units per hour) Split-seconds 30-minute recorder (subsidiary dial at 12 o'clock) 12-hour recorder (subsidiary dial at 6 o'clock) Diurnal (day-time) an.cturnal (night-time) hours with a 24-hour (AM-PM) scale (subsidiary dial at 3 o'clock)