Case #754 — Tissot PRX Chronograph Ref. T137.427.11.011.00

Case #754 — Tissot PRX Automatic Chronograph "Panda"

Ref. T137.427.11.011.00

Status: Available

Condition: Excellent Pre-Owned

Scope: Box, Papers, and Cards (warranty card present but undated)

Year: Unknown

🔎 Case Notes

The PRX is one of the few modern watches that earned its following through design rather than marketing. The name belongs to an integrated-bracelet watch with angular character and a vintage sports-watch sensibility, revived from a Tissot case shape first seen in 1978 — and the chronograph is where that shape is pushed furthest.

This is the light-dial, black-register configuration, the one the market simply calls the Panda. The dial carries a fine vertical striation pattern with black sub-seconds, 30-minute and 12-hour registers set inside a minute track, and because the case is almost entirely a study in brushed surfaces broken by polished bevels and a polished bezel, the high-contrast dial does most of the talking. The chronograph pushers sit flat and integrated at 2 and 4 o'clock, which keeps the profile clean from the side rather than cluttering the case flank.

Underneath the exhibition caseback is the reason this watch exists in its current form: the Valjoux A05.H31, essentially an ETA Valjoux 7753 upgraded to a 60-hour power reserve, a 50% increase over the standard calibre's 42 hours. Unlike most reworked ETA calibres, it keeps a conventional hairspring and the full 28,800 vph frequency.

The example presents in Excellent Pre-Owned condition, with no specific flaws recorded during BST inspection. It arrives as Box, Papers, and Cards — the warranty card is present but undated, so no remaining factory warranty period is claimed here. The integrated bracelet is currently sized to fit an approximately 8-inch wrist.

🕰️ The Evidence

• Reference: T137.427.11.011.00
• Model / Collection: PRX Automatic Chronograph (T-Classic)
• Year: Unknown
• Case: 316L stainless steel, brushed with polished bevels; tonneau / barrel form
• Case Diameter: 42 mm
• Thickness: 14.5 mm
• Lug-to-Lug: 41.5 mm
• Lug Width: 13 mm (integrated fitting)
• Dial: White/silver with black chronograph registers — "Panda" configuration; applied indexes with Super-LumiNova on dial and hands
• Crystal: Sapphire with anti-reflective coating
• Bezel: Fixed, polished
• Crown: Stainless steel push-pull crown with Tissot logo; polished oblong chronograph pushers
• Caseback: Exhibition caseback displaying the movement
• Movement: ETA Valjoux A05.H31, based on the Valjoux 7753
• Movement Type: Automatic, cam-actuated chronograph, 27 jewels, 28,800 vph (4 Hz)
• Power Reserve: 60 hours
• Functions: Central hours, minutes and chronograph seconds; 30-minute counter; 12-hour counter; small seconds; date
• Water Resistance: 100 metres
• Bracelet: Integrated stainless steel bracelet, with quick-release "interchangeable system"
• Clasp: Butterfly clasp with push-buttons
• Bracelet Fit: Approximately 8-inch wrist
• Condition: Excellent Pre-Owned
• Included: Box, Papers, and Cards (warranty card undated)

🌟 Collector Provenance

The PRX line arrived as a time-only proposition and expanded outward. Case sizes start at 35 mm, with the core three-hand model at 40 mm in both quartz and automatic form. The chronograph had to grow, because of the volume of the mechanical movement inside it — and that single engineering constraint is what separates this reference from the rest of the family.

That makes the Automatic Chronograph the structural outlier of the collection rather than simply a bigger version of it. It follows the time-only model's design language closely, but scaled up in every respect, and the proportions hold together better than the raw numbers suggest. The width-to-thickness aspect ratio is well balanced, which is why a 14.5 mm case on an integrated bracelet does not behave like a slab.

For collectors, the dial choice matters as much as the case. Panda and reverse-panda chronograph dials belong to a specific lineage of 1960s–70s sports chronographs, and Tissot applied that vocabulary to a 1978 case silhouette rather than to a round chronograph case — an unusual combination, and part of why this particular configuration reads differently on the wrist from the more commonly seen blue PRX variants.

🌟 Technical Provenance

The A05.H31 is a known quantity, and that is the point. The movement is related to the famous Valjoux 7750 automatic chronograph family, with an orientation closer to the 7753 — meaning the 3-6-9 register layout that makes a tri-compax dial symmetrical, rather than the 6-9-12 arrangement of the original 7750.

It is cam-actuated rather than column-wheel operated, which is the conventional and robust route for this calibre family. Given the proven reliability of the Valjoux chronograph architecture, retaining most of its original features is arguably a virtue.

What Tissot changed is meaningful in daily use: the jump from 42 to 60 hours of running autonomy turns a watch that dies over a weekend into one that is still running on Monday morning. The movement is finished with perlage and a custom open-worked rotor, visible through the sapphire caseback and notably well decorated for its segment.

🧾 From the Case File

This is a mechanical chronograph you can actually use. The 100-metre rating covers everything short of serious diving, the sapphire is AR-coated, and the integrated bracelet with push-button butterfly clasp sits flush against the case rather than hanging off conventional lugs — part of why the watch wears shorter than its diameter implies, helped by the 41.5 mm lug-to-lug.

Practical ownership notes: the quick-release system means a 13 mm-fitting strap can be swapped in without tools, which is the simplest way to change the watch's character entirely. The 12-hour counter and date make it usable as a single-watch chronograph, and the 60-hour reserve means a Friday-to-Monday rest doesn't require resetting.

As supplied, this example is sized to an approximately 8-inch wrist and comes with its box, papers and cards. For a buyer who wants a Valjoux-derived automatic chronograph in the Panda configuration without paying for an unworn example, the practical gap between this and new is condition grade — and here that grade is Excellent Pre-Owned with no flaws noted at inspection.

Buy with Confidence

BST guarantees the authenticity of every watch we sell and provides a 30-day mechanical performance guarantee under normal use.

Accuracy may vary with age and service history, and water resistance is not guaranteed unless specifically stated and pressure-tested.

🗝️ BST Verdict

A 1978 case silhouette carrying a 7753-derived automatic chronograph and a high-contrast Panda dial — the most mechanically ambitious member of the PRX family, and the configuration that makes the clearest visual argument.

Complete with box, papers and cards, in Excellent Pre-Owned condition, and sized for a larger wrist. A straightforward, well-understood Swiss chronograph bought on its merits rather than on hope.

👉 Every case deserves a closer look.