Tissot Seastar 1000 Powermatic 80 Silicium T120.407.11.041.01

The Tissot Seastar 1000 Powermatic 80 Silicium (reference T120.407.11.041.01) is a 43mm stainless steel automatic dive watch with a blue dial, a blue ceramic unidirectional bezel, and 300m of water resistance. It is the silicon-balance-spring version of the blue-dial, steel-bracelet Seastar 1000 Powermatic 80, driven by the ETA-derived Powermatic 80.111 caliber with an 80-hour power reserve. The case is 12.7mm thick with a 49.6mm lug-to-lug and 21mm lugs, and carries a sapphire crystal, screw-down crown and caseback, and a quick-release steel bracelet. Later production of the same blue-dial reference (T120.407.11.041.03) switched the balance spring to Tissot's Nivachron alloy while keeping the case, dial and movement otherwise unchanged.

Tissot's dive-watch lineage predates the current Seastar 1000. HiConsumption dates the Seastar name to 1952, describing it as Tissot's commitment to water-resistant timepieces, while Time and Watches places the Seastar collection's launch in 1954 and notes early references such as the T12 of 1956 (rated to 120 metres) and the monocoque-cased Seastar Seven. WatchGecko's Safie Agar-Hutton traces the line to the 1950s and Tissot's earlier Five Star series, explaining that the Seastar name signaled hermetic sealing for improved water resistance.

HiConsumption records later milestones in the modern line: a Seastar 660 in 2003 and a Seastar 1000 in 2004, the latter named for its 300-metre (30 bar) water resistance rather than a literal 1,000-metre rating. The naming convention carried forward to the automatic model that concerns this reference.

The 43mm Seastar 1000 Powermatic 80 was introduced in 2018. Time and Watches reported the launch as a 43mm x 12.7mm stainless steel diver with a unidirectional ceramic bezel, sapphire crystal, 300-metre water resistance and the automatic Powermatic 80 caliber, offered in four variations at US$695 on rubber and US$725 on bracelet. The blue-dial, blue-bezel, steel-bracelet configuration corresponds to the reference researched here; the T120.407.11.041.01 suffix denotes the version fitted with a silicon (Silicium) balance spring.

The watch runs the Powermatic 80, an automatic caliber Tissot developed from the ETA 2824-2. HiConsumption notes it lowers the oscillation frequency to 3 Hz (21,600 vibrations per hour) versus the 4 Hz of the base movement, which is how it achieves roughly 80 hours of power reserve rather than the standard 38–42 hours. Teddy Baldassarre identifies the base caliber as the ETA C07.111 and lists 23 jewels; Millenary Watches records the movement as the Powermatic 80.111 with a laser-set rate that is factory-adjusted and requires no manual regulation, and notes it is not COSC-certified.

What distinguishes this specific reference is its balance spring. WatchBase catalogs T120.407.11.041.01 as the "Silicium" version, meaning it uses a silicon (silicium) hairspring in place of a conventional alloy spring. Silicon hairsprings are non-magnetic and resist the fields produced by everyday electronics. HiConsumption cites accuracy for the Powermatic 80 of approximately -1 to +5 seconds per day, respectable for an entry-level Swiss automatic.

Tissot later revised the same blue-dial reference to T120.407.11.041.03, whose official US listing specifies a patented Nivachron balance spring rather than silicon. The two references are otherwise built on the same case and movement architecture, so the balance-spring material is the primary technical difference between the Silicium reference here and the current production version.

The 43mm case is on the larger side of a modern diver. Millenary Watches lists it at 43mm in diameter, 12.7mm thick, with a 49.6mm lug-to-lug and 21mm lugs. Reviewers of the smaller 40mm version put this size in context: HiConsumption writes that the 43mm Seastar "felt just a bit too large and chunky for many enthusiasts," which motivated Tissot's later, more compact release.

Owner feedback compiled by Millenary Watches is consistently positive on value and accuracy. Bob Osborne called it "truly a steal" and reported accuracy comparable to his Omega Seamaster. Steven Howards said the Seastar became his primary daily wearer, leaving his Datejust and Jaeger-LeCoultre on the dresser more often. KenS, a multi-watch collector, wrote that he was "trying to think of anything that those watches can do that my Seastar can't," citing accuracy he rated above a former Rolex Submariner and a current Omega Seamaster, and Gary Hill described the value proposition as "insane."

These impressions are drawn from owner reports rather than a single controlled review, and they focus on daily wearability, timekeeping and value rather than dive use. The consistent theme is that the watch punches above its price on accuracy and everyday practicality, with size being the main reservation for smaller wrists.

At launch, Time and Watches lists four 43mm variations: a black dial with black bezel on rubber; a blue dial with blue bezel on steel bracelet; a black dial with black bezel on steel bracelet; and a silver dial with black bezel on steel bracelet. The reference researched here is the blue-on-blue bracelet configuration.

Within that blue-dial bracelet configuration, Tissot has produced more than one reference. WatchBase catalogs T120.407.11.041.01 as the "Silicium" version with a silicon balance spring, while the current Tissot US site lists the visually equivalent T120.407.11.041.03 with a Nivachron balance spring. Buyers cross-shopping listings should treat these as different production generations of the same watch rather than different models.

Tissot subsequently broadened the Seastar 1000 range beyond the original 43mm case. HiConsumption and other outlets covered a 40mm Powermatic 80 version that reviewers found more wearable and versatile than the 43mm, and the collection also includes smaller quartz variants. The 43mm Silicium reference here belongs to the original, larger automatic generation that opened the modern Seastar 1000 Powermatic 80 line.

At its 2018 introduction, Time and Watches reported US pricing of $695 for the rubber-strap versions and $725 for the steel-bracelet versions of the Seastar 1000 Powermatic 80, which is the launch MSRP applicable to this blue-dial bracelet reference. Tissot has since raised pricing on the line: the current blue-dial bracelet reference (T120.407.11.041.03) is listed at $925 on the official Tissot US site.

The specific Silicium reference T120.407.11.041.01 appears to have been superseded by the later Nivachron reference. A Klarna US listing for this exact reference notes that there are no shops currently selling the product, consistent with it being discontinued in favor of the current version. Buyers seeking the equivalent watch new should expect to find the Nivachron reference through authorized dealers such as Teddy Baldassarre and Tissot's own retail channels.

Because the Silicium and Nivachron references share the same case, dial, bezel and movement architecture, shoppers deciding between a remaining Silicium example and a new Nivachron one are largely choosing between two balance-spring materials at potentially different prices, rather than between meaningfully different watches.