SKU Code: GMT/SS/B/QZ

This stainless-steel GMT dual time zone watch is one of our latest models and is powered by the high-performance Ronda 515.24 quartz GMT movement. It features an anti-reflective, impact-resistant sapphire crystal, a scratch-resistant ceramic bezel, and a robust 300m / 1000ft water-resistant steel case.

The watch is perfectly suitable for swimming, snorkelling, and general water sports. While the water resistance itself is more than adequate for diving, it’s worth noting that—as a GMT watch—the bezel is designed for tracking a second time zone rather than dive timing, so its functionality is more limited for that specific purpose.

GMT Function Explained

The appeal of a GMT watch lies not in complexity, but in its elegant simplicity. On a conventional watch, the hour hand completes one full rotation every 12 hours. A GMT watch adds a second hour hand that completes just one rotation every 24 hours.

A corresponding 24-hour scale—usually on the bezel—allows the wearer to read a second time zone at a glance. Because the GMT hand operates on a true 24-hour cycle, there is no ambiguity between a.m. and p.m., making it exceptionally intuitive and easy to use. This is also why GMT watches can, at first glance, resemble diver’s watches.

Designed for Aviation & Long-Range Travel

These watches were originally developed for long-haul airline pilots and military transport aircrew, including those flying aircraft such as the C-130 Hercules and Airbus A400M. The GMT function allows pilots to instantly reference both departure and destination time zones—an essential requirement for long-range operations.

Case Size

• 45mm including crown
• 40mm excluding crown

Dimensions & Specifications

• Water Resistance: 300m / 1000ft
• Movement: Ronda 515.24 GMT Quartz
• Case: Stainless Steel
• Bezel: Ceramic, scratch-resistant
• Crown: Screw-down
• Thickness: 15mm
• Crystal: Sapphire with anti-reflective coating
• Crystal Diameter: 31mm
• Lug-to-Lug: 49mm
• Straps: 2 × 20mm NATO webbing straps (Black & Grey)

For full operating details of the Ronda 515.24 GMT movement, please see:
https://www.ronda.ch/fileadmin/user_upload/Products/TA_BA/ba/5XX.24/BA_505-24.515-24_e.pdf

Why Sapphire Crystal?

We’re often asked why sapphire crystal is superior to standard mineral glass. Simply put, synthetic sapphire is the strongest and most scratch-resistant material available for watch crystals.

From our experience, over 90% of cracked crystals we encounter—even with hardened mineral glass—are mineral rather than sapphire. Sapphire crystals are exceptionally durable because they are heat-treated to remove internal stresses, then finished with dual anti-reflective coatings for clarity and strength.

These characteristics make sapphire especially popular with military personnel, security professionals, police officers, and those with active outdoor lifestyles—groups that account for over 70% of our customer base. It’s no coincidence that sapphire crystal is now also used on the latest iPhone models.

Sapphire does come at a higher cost, which is why it’s typically reserved for higher-end watches—but in demanding environments, the durability more than justifies it.