An original Baume & Mercier ultra-thin pocket watch movement featuring a 40.4 mm dial size and an impressive thickness of only 3.7 mm. This is a finely made high-grade Swiss movement, reflecting the precision and craftsmanship for which Baume & Mercier has long been respected. The balance appears to be in good condition, and the movement runs briefly before stopping. Due to its age, it is offered as requiring a complete service before regular use. A suitable piece for restoration, collecting, or as a source of authentic vintage parts. Founded in 1830, Baume & Mercier is one of Switzerland’s oldest watch manufacturers, renowned for producing elegant, high-quality timepieces with exceptional finishing. During the late 19th and early 20th centuries, the company manufactured a wide range of finely crafted pocket watches, many featuring slim, refined movements designed for both reliability and sophistication. Ultra-thin pocket watch movements such as this one demonstrate the advanced engineering of the period, combining compact dimensions with precise mechanical construction. Today, original Baume & Mercier movements are appreciated by collectors and restorers for their quality, historical significance, and suitability for authentic restoration projects.