To preserve the precision of the watch, Tissot developed a new, titanium-based alloy that is used to create the Nivachron balance spring. This spring is far more resistant to magnetic fields than other balance springs.
It all comes together with the dial, the blue gradient on the dial looks luscious and deep. A lot of diver’s watches attempt to replicate the ocean depths on their dial, but the Seastar does an excellent job of replicating the mid-level depth of water. It isn’t so much the absolute ocean depths but like the green/blue of the shallower regions. The imprinted wave pattern also adds to this effect. It looks like you’re staring up at the surface of the ocean from its depths.
It does have two other dial variants, one in a darker blue (ref. T120.607.11.041.01) and one in black (ref. T120.607.17.441.00). Neither quite capture the magic of the lighter blue/green variant but are by no means ugly, they’re just a little more generic. The black does change up the strap to be a rubber one which gives it a sportier and casual look.