This is an 18K rose gold A. Lange & Sohne 1815 Chronograph, 402.032. It has a leather strap with a matching 18k rose gold tang buckle, and a scratch resistant sapphire crystal. It has a transparent sapphire display case back secured with 6 screws. The 39.5mm diameter case, rounded bezel, downturned lugs, rectangular chronograph pushbuttons, and winding crown are all polished. The dial is silver with black painted Arabic numeral hour markers, blued alpha hands, a centered sweep chronograph hand, and an outer minute track. The chronograph has a Flyback function that lets the stopwatch be instantaneously restarted for continuous events without stopping or being reset. The chronograph minute hand doesn't continuously move, but jumps in 1-minute increments, allowing for an accurate reading of the timing function. It has stop seconds - pausing the second hand when the crown is pulled out in order for the time to be set accurately. There is a 30-minute subsidiary dial between 3 and 4 o'clock, and a constant seconds sub dial between 8 and 9 o'clock. It's water resistant to 30 meters/100 feet, and there is a 60-hour power reserve at full wind. The 10.8mm thick case, dial, and movement are all signed. The automatic self-winding A. Lange & Sohne caliber L951.1 movement is made from Glashütte 3/4 plate, with fausses cotes embellishment. It's constructed with 34 jewels, 4 in screw-mounted gold châtons, and a shock absorber mechanism. It includes a straight-line lever escapement, a monometallic balance that's adjusted to 5 positions. There is a self-compensating Breguet balance spring, a swan-neck micrometer regulator, and a hand-engraved balance bridge. Each component of the movement has fine polished beveled edges, and a hand-engraved balance cock. The rotor oscillates at a frequency of 18,000 vph.