Here is the HydroConquest GMT tuned for summer: a sunray blue dial on a blue rubber strap. The Longines L3.790.4.96.9 has a coordinated, sporty look, and the strap makes the 41mm diver light and comfortable on your wrist from morning swim to evening flight.

Under the dial runs the exclusive Longines L844 automatic. It adds a 24-hour GMT hand, so you can track a second time zone without doing mental math, and its silicon balance spring gives roughly ten times the magnetic resistance required by ISO 764. The power reserve is around 72 hours. Add a ceramic bezel, screw-down crown and 300 meters of water resistance, and you have a watch that is as practical underwater as it is in an airport.

The rubber strap dries fast and stays comfortable in heat. The 12.9mm-thick case sits low enough to wear with a casual shirt.

Inside the blue-on-blue HydroConquest GMT (L3.790.4.96.9)

• Case: stainless steel, 41mm wide, 12.9mm tall
• Dial: sunray blue, luminous hands and markers, date window
• Bezel: unidirectional, ceramic insert
• Movement: Longines L844 self-winding GMT, silicon balance spring
• Power reserve: approximately 72 hours
• Water resistance: 300m (30 bar)
• Strap: blue rubber, 21mm lug width

Bright, light and seriously capable. It is the HydroConquest GMT for people who spend as much time in the water as in the air.