A. Lange & Söhne Langematik Perpetual

The A. Lange & Söhne Langematik Perpetual, reference 310.025 E, has a perpetual calendar in a 950 platinum case. The case measures 38.5 mm across and 10.2 mm high, has a see-through back and is water resistant to 30 metres. A black alligator leather strap fastens with a platinum pin buckle. Self-winding calibre L922.1 contains 478 parts and incorporates a ZERO-RESET mechanism. The movement beats at 21,600 semi-oscillations per hour and has a 46-hour power reserve. The grey dial carries an outsize date, weekday and moon-phase displays and a day/night indicator.