“It first appears in 1906: a pair of brackets around a dial displaying Roman numerals and a sapphire cabochon-set winding crown…features that are characteristic of the Cartier style inaugurated by this emblematic watch.  With the Santos watch, and later the Tank watch, the Tonneau watch constitutes a fundamental creation in watch making according to Cartier.  A seemingly simple shape – that of the barrel to which it owes its name – within which lies an intricately crafted form: oblong, curved, totally avant-garde with etched dial that snugly fits to the shape of the wrist.  The Cartier Tonneau comes in two sizes (small and large) in rose gold, white gold, and platinum on leather strap.  Some models are embellished with diamonds.  The Cartier Tonneau is equipped with a manual-winding movement in all models, and is water resistant up to a depth of 30 meters ” - Cartier