For nearly a decade, the A. Lange & Söhne Lange 31 has been the first and only mechanical wristwatch with a power reserve of 31 days and a patented constant-force escapement that continuously delivers uniform torque. Last week at the SIHH 2017 in Geneva, A. Lange & Söhne unveiled a new variation of the Lange 31 —up until now only available in platinum as ref. 130.025 or in 18K rose gold as ref. 130.032— in 18K white gold with a grey dial. This new watch is limited to 100 watches.