Designed in 1917 by Louis Cartier, the Cartier Tank is probably the most emblematic model from the Cartier manufacture. It was introduced in 1918, and entered full production in 1919, when six pieces were built. Its lines and proportion are inspired by the Renault tanks used on the Western Front during the First World War. The model has undergone many variations including the Tank Louis in 1922, the Tank Americaine in 1989, and the Tank Française in 1996… The pursuit of a water-resistant wristwatch with right angles, was not an easy task for Cartier. Nonetheless, in 1932, the French watchmaker launched the Cartier Tank étanche – same year as the Cartier Pasha. Its unveiling, in a vase filled with water, created quite a stir. The model arrived later on the US market, in the 1940’s. The model takes its structure from the Tank à Guichets. However, the dial flange, which extends over the side-pieces, cancels out the interplay of perpendicular lines and significantly alters the proportions of the case. For this reason, it is recorded in the Cartier archives as a Tank dérivée. Unfortunately, due to the square shape of the case, this model did not meet waterproofing expectations. Few were made which makes this watch one of the rare witnesses to Cartier's research into water-resistance. Up to this day, it has not yet been reissued by Cartier.