The watch features a square stainless steel case (37mm x 37mm) with a thickness of approximately 11.1mm to 13mm, depending on the specific measurement source.  It houses a black lacquered dial devoid of numerals, utilizing luminous index hour markers and bold hands for visibility.  Distinctive elements include a date window at the 3 o'clock position and a small seconds sub-dial at 6 o'clock, maintaining the classic Monaco layout without the full chronograph function.  The dial is protected by a domed, scratch-resistant sapphire crystal. 

The TAG Heuer Monaco WAW131A features a 37mm x 37mm square stainless steel case with a thickness of 11.1mm to 13mm (sources vary slightly).  It is fitted with a fixed polished steel bezel and a domed, scratch-resistant sapphire crystal.  The dial is black lacquered with luminous index hour markers, a date window at 3 o'clock, and a small seconds sub-dial at 6 o'clock. 

• Lug Width: 22mm

• Water Resistance: 100 meters (10 ATM)

• Case Back: Solid stainless steel

• Strap: Black alligator leather with a polished steel folding clasp featuring double safety push-buttons. 

• Crown: Push/pull style (non-screw-down).

The watch is powered by a Swiss Quartz movement (battery-operated), emphasizing precision and low maintenance over mechanical complexity.  While TAG Heuer does not publicly disclose the specific third-party caliber number (e.g., ETA or Ronda) for this reference in standard documentation, the technical performance is characterized by:

• Movement Type: Swiss Quartz

• Functions: Hours, Minutes, Seconds (via sub-dial), and Date. 

• Frequency: 28,800 bph (4 Hz) – Note: This high frequency is typical for smooth sweeping seconds hands in some quartz movements, though standard quartz usually ticks once per second; some sources cite this frequency specifically for the WAW131A.

• Jewels: 28 jewels (as cited in specific market data). 

• Power Source: Replaceable battery.