Tissot Seastar watches

The Tissot Seastar is the brand's dive watch line, built around the Seastar 1000, named for its 1,000 ft water resistance, and the deeper-rated Seastar 2000 Professional, good for 600 m. Both carry a diver's bezel over a sapphire crystal, and the line runs from small quartz three-handers to large automatic chronographs.

The T120 Seastar 1000 takes three main forms. The 43 mm Powermatic 80 is the core automatic. Its movement descends from the ETA 2824-2, slowed to 21,600 vibrations per hour for an 80-hour power reserve. It comes in steel or with black, rose-gold or yellow-gold PVD, often with a gradient dial, on a bracelet, mesh, rubber or fabric. The 45.5 mm quartz chronograph keeps the same bezel and gradient dials in blue, grey, green and red. The 36 mm quartz three-hander, under 10 mm thick, is the small one, in steel or two-tone.

The earlier T066 Seastar 1000 had a 42 mm three-hand automatic and a 48 mm automatic chronograph more than 17 mm thick, including versions named Ceramic. The Seastar 1000 Professional Limited Edition (T120.614) is a 48 mm blue-dial piece from the T120 series.

The Seastar 2000 Professional is the serious diver. It has a helium escape valve at 9 o'clock, a unidirectional steel bezel with a polished ceramic insert, and a 46 mm case close to 16 mm thick. The dial is engraved with a wave pattern and darkens towards the edge, with the date at 6 o'clock and large fence-post hands. It runs on the Powermatic 80 with a Nivachron balance spring, and its lugs take a 22 mm strap.