Introduced in 1948, Calibre 481 introduced a signature complication to the market: the power reserve indicator or "Réserve de Marche". It evolved from the first automatic movement from Jaeger-LeCoultre, the JLC 476 and features bumper automatic winding.
The JLC 481 was introduced in the Jaeger-LeCoultre Powerwind, Ref E 163, and was the first production watch from any company with a power reserve indicator. Although the movement has been updated, this product line has continued to today, with the name Powermatic, Futurematic, and Réserve de Marche.
The signature power reserve indicator disc is located at 12:00 on the movement. It is marked with numerals for "0 • 10 • 20 • 30 • 40" with a "red zone" from about 14 on this scale to well below "0". The disc rotates counter-clockwise. The "481" marking is difficult to see as it is located below the balance wheel. The bumper rotor has two springs; one fixed to the rotor and another attached to the bumper.