Cartier, Tank Obus "Shell Tank" antique watch, 18K gold case, classic four-corner spherical protruding column shape, quartz movement, eagle head precious metal mark, produced in Paris in the 1980s. The case and dial are designed as one piece, with red enamel Roman numeral hour markers filled inside. The small square dial in cream white is printed with "CARTIER PARIS", creating a full retro atmosphere. The Obus is a highly recognizable niche model in the Cartier Tank family. Different from the ordinary Tank, the rounded and pointed tips at the four corners are its soul. The well-preserved blue enamel hour markers are extremely rare. It is delicate and compact to wear, making it suitable for both antique collection and wearing.