A Lange & Söhne latest version of its 1815 Chronograph comes with a stopwatch function, and features a jet black dial with a pulsometer scale, encased in white gold.

Lange & Söhne has been crafting models with stopwatch functions since 1999, fitted with sapphire-crystal casebacks like all other Lange watches.

The new watch belongs to the 1815 collection, which gets its name from the birth year of Ferdinand A. Lange, who founded the manufacture in Glashütte, Germany in 1845.

The 1815 Chronograph was added to the 1815 family in 2004 and in 2010 was endowed with a new L951.5 movement, which has a power reserve of 60 hours and a manufactory-made free-sprung balance spring. 

The movement beats at a frequency of 18,000 semi-oscillations per hour (2.5 hertz), and can measure times with an accuracy of one fifth of a second.

The new 1815 Chronograph comes in a 39.5-mm white gold case and has a stopwatch function. 

Its rhodium hands ensure superb legibility against the backdrop of a jet black solid-silver dial. 

Heart rates can be determined with the pulsometer scale on the outer ring of the dial. It is graduated from 40 to 200 beats. When the time for 30 beats is measured, the peripheral scale indicates the heart rate per minute. 

A sapphire-crystal case back reveals the architecture and lavish finish of the movement. It shows the column wheel that controls the chronograph functions, the levers of the fly back mechanism, and the snail of the precisely jumping minute counter. The escapement is visible as well. 

Hallmarks of the Lange style include the whiplash spring of the precision beat-adjustment system on the hand-engraved balance cock.

The watch is characterised by its contrasts between light and dark, further underscored by a black alligator leather strap and a solid white-gold Lange prong buckle.

Launched in June this year, the new 1815 Chronograph is priced at around $50,000.