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, medium model, quartz movement. Case in 18K yellow gold, beaded crown set with a sapphire, grained silvered dial, blued-steel sword-shaped hands, mineral crystal, strap in dark gray alligator skin, ardillon buckle in 18K yellow gold.