Worn by Louis Cartier himself, the “Tank Louis Cartier” watch sets the standard for all Tank watches. To embody Louis Cartier's contribution to “modern style”, later known as Art Deco, the tops of the lugs were rounded in contrast to the previously fashionable rectangular form and proud lines. Tank Louis Cartier watch, small model, Manufacture mechanical movement with manual winding, caliber 8971 MC. Case in 18K rose gold, beaded crown set with a sapphire cabochon, silvered beaded dial, blued-steel sword-shaped hands, mineral crystal, strap in shiny brown alligator skin, ardillon buckle in 18K rose gold.