Tissot · Seastar 1000 and PRX

Tissot T1208071105100 vs Tissot T1374071109100

11 published specifications differ between these two, and 4 are identical. Every figure below is what the manufacturer states for that reference; nothing is inferred from the other watch.

What differs

Specification	Tissot Seastar 1000 40mm Powermatic 80, black dialT1208071105100	Tissot PRX 40mm Powermatic 80, green dialT1374071109100
Case	316L stainless steel, 40.00 mm, with screw-down crown and caseback	316L stainless steel, 40.00 mm wide by 39.50 mm long
Thickness	12.48 mm	10.93 mm
Lug to lug	40 mm	39.5 mm
Lug width	20 mm	12 mm
Water resistance	Water-resistant up to a pressure of 30 bar (300 m / 1000 ft) with screw-down crown	Water-resistant up to a pressure of 10 bar (100 m / 330 ft)
Bezel	316L stainless steel with mineral ring, anti-clockwise rotating, with Super-LumiNova on the case	Stainless steel
Dial	Black, with index markers and Super-LumiNova on the hands	Green, with index markers and Super-LumiNova on the hands
Case back	Screw-down and see-through caseback	See-through caseback
Bracelet	Stainless steel, reference T605049459, interchangeable quick release	Stainless steel, reference T605046447, interchangeable quick release
Clasp	Folding clasp with safety lock and push-buttons	Butterfly clasp with push-buttons
Movement notes	Patented Nivachron balance spring. Date. Total weight 148.00 g. Country of manufacture given as Switzerland, with a stated two-year warranty. Tissot does not name a calibre on this page.	Patented Nivachron balance spring. Date. Total weight 138.00 g. Country of manufacture given as Switzerland, with a stated two-year warranty. Tissot does not name a calibre on this page.

What is identical

Worth knowing as much as the differences: these are the specifications you cannot use to tell the two apart.

Diameter: 40 mm
Crystal: Sapphire with one antireflective coating on bottom side
Movement: Swiss automatic
Power reserve: 80 hours

Stated for one, not the other

These rows cannot be compared, because one maker publishes the figure and the other does not. An empty cell is a gap in the manufacturer's documentation, not a gap in the watch — and not a licence to fill it in from the other column.

Crown	Screw-down	not stated

What the differences cost you

Each note below follows from the published figures in the tables above — what they mean for intake, for a listing, and for the handover. Nothing here estimates a price or a margin.

A visible difference in how they wear

1.6 mm of thickness separates these, with the T1208071105100 the taller at 12.5 mm. That is the difference between a watch that goes under a cuff and one that catches on it — worth a photograph from the side rather than a number in a table.

Do not describe these the same way

300 metres on the T1208071105100 against 100 on the T1374071109100 — not a variation on the same watch but a different class of one, built around a case and crystal designed for depth. Expect different buyers, different questions, and a different service conversation. Never carry the T1208071105100's rating into the T1374071109100's listing.

What to check on each

T1208071105100

Grade the bezel ring as mineral. Tissot specifies a mineral bezel ring here, which scratches in a way ceramic and sapphire inserts do not, so surface marking is expected wear rather than a defect.
Confirm the bezel turns anti-clockwise only. Tissot describes it as anti-clockwise rotating, so any clockwise movement at all is a failure of the safety design.
Thread and unthread both the crown and the caseback if you can. This reference specifies screw-down on both, and the published 30 bar rating is stated as conditional on the screw-down crown.

T1374071109100

Treat the bracelet as part of the case. At a published 12 mm lug width on a 40 mm watch, this is an integrated design and a damaged or missing bracelet is not solved by fitting a strap from the drawer.
Record the bracelet reference T605046447 and check it against the watch. Bracelets are model-specific here and a bracelet from another PRX will not sit correctly.
Work the butterfly clasp repeatedly and check both sides latch. A butterfly clasp hides its mechanism inside the bracelet, so it is rarely inspected and its springs carry the whole weight.

Sources

Not affiliated with Tissot. Specifications are read from each manufacturer's own published documentation on the dates shown and may change; the manufacturer's current documentation governs.