Tissot PRX 40mm T1374071109100: specifications and what to check

Twelve millimetres is not a strap size

The published lug width is 12.00 mm on a case 40.00 mm wide. That combination tells you everything about how this watch is built.

It is an integrated bracelet design: the bracelet is shaped to continue the case rather than hang from it, and the attachment point is narrow and hidden inside the case profile. There is no meaningful aftermarket in 12 mm straps for a watch this size, because the number is not describing a strap opening in the usual sense.

Three consequences that all land on the dealer.

A damaged bracelet is a damaged watch. On a 20 mm lug watch, a ruined bracelet costs you a strap. Here it costs you a model-specific part, and the watch is close to unwearable without it.

Record the bracelet reference. Tissot publishes it: T605046447. A bracelet from a different PRX will not sit flush against this case, and the mismatch shows as a gap at the join.

Check for stretch and for missing links before you agree a number, and ask where the removed links went.

The clasp you cannot see

The closure is a butterfly clasp with push-buttons — it folds into itself so the bracelet reads as unbroken around the wrist.

Hidden clasps get inspected least and carry the most. Open and close it a dozen times. Both wings should release evenly when you press, both should snap shut positively, and the whole assembly should sit flat rather than bowed.

Then hang the watch from the closed clasp and give it a gentle pull. On a 138-gram watch, a clasp that opens under load is how a sale becomes a liability.

Tissot also lists the bracelet as interchangeable quick release. Test that too: pop the bracelet off and refit it once. The tab is a tiny moving part, it seizes, and a seized one means the feature you are advertising does not work.

What the page does and does not say about the movement

Tissot publishes: Swiss automatic, 80 hours of power reserve, a patented Nivachron balance spring, and a date.

It does not publish a calibre name, a jewel count, a frequency or a daily accuracy figure.

Write what is published. "Swiss automatic, 80-hour power reserve, Nivachron balance spring" is accurate, complete and defensible. Naming a movement Tissot has not named on this page is a claim you cannot support if a buyer checks.

The 80 hours is worth emphasising in its own right — it means the watch survives a weekend off the wrist, which most of the shorter-reserve watches documented on this site do not. Wind it fully, put it down Friday, and confirm it is still running Monday.

Case, crystal and rating

316L stainless steel, 40.00 mm wide and 39.50 mm long — Tissot gives both, because the case is not round.

10.93 mm thick, 138.00 g, with a see-through caseback.

The crystal is sapphire with one antireflective coating on the bottom side. Note the singular: the coating is on the inner face only, so interior haze means a crystal change rather than a polish, and there is no top coating to damage.

Water resistance is 10 bar (100 m / 330 ft). Tissot does not describe a screw-down crown for this reference, unlike its Seastar references, so the rating rests on a crown that is simply pushed home.

Also published and worth quoting: Country of manufacture: Switzerland, and a stated two-year warranty from new.