The Vacheron Constantin Historique Ultra-fine 1955 timepiece currently holds the title of the “world’s thinnest mechanical hand-wound watch,” at just 4.10 mm thick. It is powered by a the Calibre 1033, which is merely 1.64 mm thick. For 2010, Vacheron Constantin remade this model in 18k rose gold, to celebrate its 55th anniversary. The gold case is 36 mm in diameter and comes with a square-scaled alligator leather strap with an 18k rose gold buckle and polished half Maltese cross. Water-resistance is 30 meters.