The Longines HydroConquest GMT (Model L3.790.4.56.9) is a premium Swiss diving watch featuring a built-in multiple
time zone mechanism. This specific reference pairs a 41mm stainless steel case with a striking sunray black dial and a matching black rubber strap. [1, 2]
Technical Specifications

Movement: Longines Calibre L844 automatic movement.
Power Reserve: 72 hours.
Water Resistance: 30 bar (300 meters / 1000 feet).
Case Size: 41 mm diameter, 12.9 mm thickness.
Bezel: Unidirectional rotating bezel with a black ceramic insert.
Crystal: Scratch-resistant sapphire crystal with anti-reflective coating.
Special Features: True "traveler's" GMT complication, silicon balance-spring for high magnetic resistance, and a date display at 3 o'clock.