Product Information
* Factory: ZF Factory
* Brand: Tudor
* Collection: Black Bay GMT
* Reference: M7939G1A0NRU-0003
* Case Size: 39 mm
* Case / Bracelet: Full Steel
* Dial: Black Dial
* Bezel: Aluminum Bezel
* Movement: 2824 Automatic Movement
* Crystal: Sapphire Crystal
Technical Specifications
* Measured Case Diameter: 39.0 mm
* Measured Case Thickness: 12.8 mm
* Measured Weight: 153.4 g*
* Movement: 2824 Automatic Movement
* Beat Rate: 28,800 BPH
* Crystal: Sapphire Crystal
* Bezel: Aluminum
*The 153.4 g weight is the actual measurement of the individual watch inspected. Bracelet sizing, production tolerances and individual assembly may result in minor differences between watches.
Timegrapher Test Results
* Daily Rate: +12 Seconds/Day
* Amplitude: 321°
* Beat Error: 0.2 ms
* Beat Rate: 28,800 BPH
Testing Note
These readings were recorded from this individual watch during its pre-shipment QC inspection.
Mechanical movement readings can vary according to power reserve, watch position, ambient temperature and testing conditions. The recorded +12 seconds/day represents the movement’s performance at the time of inspection rather than a permanently fixed daily rate.
For this QC inspection, the +12 seconds/day result remains within the reference range used for pre-shipment testing. The daily rate should still be evaluated together with amplitude, beat error and actual functional operation.
2824 Automatic Movement Performance
This ZF Factory Tudor Black Bay GMT M7939G1A0NRU-0003 is equipped with a 2824 automatic movement operating at 28,800 vibrations per hour.
The recorded results were:
* Daily Rate: +12 Seconds/Day
* Amplitude: 321°
* Beat Error: 0.2 ms
* Beat Rate: 28,800 BPH
The recorded data showed stable operation under the testing conditions.
In addition to timegrapher readings, pre-shipment inspection should include automatic winding, manual winding, crown operation, time setting, date operation and available GMT functions.
39mm Case and 12.8mm Thickness
The individual watch inspected measured:
* Case Diameter: 39.0 mm
* Case Thickness: 12.8 mm
* Measured Weight: 153.4 g
The combination of a 39 mm diameter and 12.8 mm measured thickness gives this Black Bay GMT relatively compact proportions while retaining the physical presence expected from a full-steel sports watch.
The 153.4 g measured weight should be considered together with the bracelet configuration and case dimensions when evaluating the actual wrist feel.
These measurements apply to the individual watch inspected rather than representing guaranteed measurements for every production piece.
Aluminum Bezel Inspection
The aluminum bezel is one of the defining exterior components of this reference.
Compared with ceramic, aluminum has a different surface appearance and tactile character, making the bezel insert and its alignment particularly important during QC.
Inspection should include:
* Bezel rotation
* Rotation resistance
* Bezel insert alignment
* 12 o’clock marker alignment
* Printed scale condition
* Surface consistency
* Excessive lateral play
* Bezel security
The bezel should rotate consistently without abnormal looseness or sticking.
Black Dial and GMT Display Inspection
The black dial provides a high-contrast background for the hands, markers and GMT indications, making alignment relatively easy to inspect.
QC should focus on:
* Dial surface condition
* Printing consistency
* Hour-marker alignment
* Main hand alignment
* GMT hand alignment
* Date-window positioning
* Date numeral centering
* Dial cleanliness
For a GMT model, functional inspection is especially important because the additional hand and date system introduce more operational elements than a simple three-hand watch.
Sapphire Crystal Inspection
The watch uses a sapphire crystal.
Pre-shipment QC should check:
* Crystal clarity
* Surface condition
* Installation
* Edge condition
* Visible scratches or damage
* Dial visibility
The crystal should sit correctly within the case and provide a clean, unobstructed view of the dial.
Full-Steel Case and Bracelet
The full-steel construction contributes significantly to the 153.4 g measured weight and overall wearing feel.
QC inspection should cover:
* Case brushing
* Polished surface transitions
* Lug finishing
* Bracelet-link finishing
* Link articulation
* Bracelet alignment
* Case-to-bracelet integration
* Clasp operation
* Clasp locking security
The bracelet should articulate smoothly while the clasp should close and lock securely.
ZF Factory and Tudor Version Position
ZF has been producing Tudor-related versions for an extended period and is one of the more established manufacturers commonly compared for Tudor models.
Within the current market, ZF is often regarded as one of the stronger options for this brand, particularly when evaluating overall case finishing, dial execution, bracelet construction and assembly consistency.
Rather than describing any single manufacturer as an absolute market leader, actual QC provides a more useful basis for comparison.
For this Black Bay GMT, the most relevant areas are:
* Movement performance
* Case dimensions
* Dial and GMT-hand alignment
* Aluminum bezel execution
* Sapphire crystal
* Case finishing
* Bracelet construction
* Overall assembly
Based on the individual watch inspected, the current ZF configuration showed a good level of consistency across these areas and remains one of the Tudor versions worth comparing and considering.
QC Observations
This ZF Factory Tudor Black Bay GMT M7939G1A0NRU-0003 recorded:
* +12 seconds/day
* 321° amplitude
* 0.2 ms beat error
* 28,800 BPH
* 39.0 mm measured diameter
* 12.8 mm measured thickness
* 153.4 g measured weight
The 2824 automatic movement showed stable operation under the recorded testing conditions.
From an exterior perspective, the aluminum bezel, black dial, sapphire crystal, steel case and bracelet should be evaluated as a complete assembly. On the inspected watch, the overall execution showed a good level of consistency.
ZF is one of the more established factory options associated with Tudor models in this market. The inspected example demonstrated a balanced combination of movement performance, case proportions, bezel execution, dial presentation and full-steel construction.
Individual pre-shipment QC remains important, particularly for GMT-hand alignment, bezel operation, date function, bracelet assembly and movement readings.
Pre-Shipment QC Inspection
* ✔️ 2824 automatic movement checked
* ✔️ Timegrapher readings recorded
* ✔️ +12 seconds/day rate documented
* ✔️ 321° amplitude recorded
* ✔️ 0.2 ms beat error recorded
* ✔️ 28,800 BPH beat rate confirmed
* ✔️ Automatic winding checked
* ✔️ Manual winding checked
* ✔️ Crown operation checked
* ✔️ Time-setting function checked
* ✔️ Date operation checked
* ✔️ Available GMT functions checked
* ✔️ Case diameter measured at 39.0 mm
* ✔️ Case thickness measured at 12.8 mm
* ✔️ Individual watch weight measured at 153.4 g
* ✔️ Sapphire crystal inspected
* ✔️ Aluminum bezel operation checked
* ✔️ Bezel alignment inspected
* ✔️ Black dial surface checked
* ✔️ Hour-marker alignment inspected
* ✔️ Main and GMT hand alignment checked
* ✔️ Date-window positioning inspected
* ✔️ Steel case finishing checked
* ✔️ Bracelet articulation inspected
* ✔️ Bracelet-to-case integration checked
* ✔️ Clasp locking function checked
* ✔️ Overall exterior assembly inspected
* ✔️ Final pre-shipment QC inspection completed
