A world first, this magnificent 45.9mm Lange & Söhne boasts a staggering 31-day power reserve! The hand-made, key-wound movement of this solid platinum Lange 31, features a superior stacked twin barrel winding system (occupying 3/4 of its diameter) and special constant force escapment visible beneath the sapphire crystal case back. The elegant frosted silver dial with applied batons displays the 31-day power reserve, subsidiary seconds and signature large date. In perfect, untouched condition and complete with special winding keys, box, certificate and instructions.