Audemars Piguet Royal Oak Perpetual Calendar Openworked 26685XT – New Calibre 7139 with BMG Titanium

A New Generation for AP's Perpetual Calendar

Audemars Piguet has unveiled the Royal Oak Selfwinding Perpetual Calendar Openworked 26685XT, powered by the new Calibre 7139. According to Monochrome Watches, this represents a clear generational shift for one of the Royal Oak's most demanding complications, combining an openworked dial with an ultra-thin automatic movement that integrates all perpetual calendar functions into a single layer.

The perpetual calendar has been an integral part of Audemars Piguet's history since 1984, when it first appeared in the Royal Oak. With the introduction of Calibre 7139, AP signals a significant evolution in how this complication is executed, drawing on the brand's RD#2 research and the Royal Oak Perpetual Calendar Ultra-Thin.

Case Construction: Titanium Meets Bulk Metallic Glass

At 41mm in diameter and just 9.5mm thick, the case impresses with its balance. This is a perpetual calendar that feels slimmer and more wearable than earlier openworked Royal Oak QPs. The construction combines lightweight titanium with AP's proprietary Bulk Metallic Glass (BMG), used for the bezel, caseback frame, and bracelet studs. The satin-brushed titanium contrasts with the mirror-polished BMG flashes of a liquid-like glow.

On the wrist, the watch wears flatter and more planted than expected, thanks to the integrated bracelet and reduced thickness. The titanium bracelet with BMG studs is light, fluid, and exceptionally well finished. The improved 50m water resistance strengthens the sense that this is a perpetual calendar designed to be worn, not handled with caution.

The Openworked Dial

The sapphire dial exposes Calibre 7139 while retaining a surprisingly good level of legibility. The layout follows a logical European order: day at 9 o'clock with an integrated 24-hour indicator, date at 12, month and leap year at 3, and the moon phase at 6. Week numbers are printed on the inclined inner flange.

Calibre 7139: All-in-One Crown System

The coolest feature from a user's perspective is the all-in-one crown system for all functions. No recessed correctors, no tools, no anxiety. There are four crown positions: winding (normal), calendar adjustment (middle position), time setting (full pull), and a special correction position for day, week number, and moon phase. The no-correction zone is marked in red on the 24-hour indicator within the 9 o'clock subdial.

Key Specifications

Availability

The Royal Oak Selfwinding Perpetual Calendar Openworked 26685XT is available exclusively through Audemars Piguet boutiques. Production will be highly limited, reinforcing the watch's position as one of the most technically ambitious references in the current Royal Oak lineup.

Frequently Asked Questions

What is Bulk Metallic Glass (BMG)?

Bulk Metallic Glass is an amorphous metal alloy with a non-crystalline atomic structure, giving it a liquid-like reflective quality and exceptional hardness. AP uses it for bezels and case components as a visually striking alternative to traditional metals.

How does the all-in-one crown system work?

The crown at 3 o'clock controls all calendar adjustments through four positions. The middle position adjusts date (clockwise) and month/leap year (counter-clockwise). A special correction position, reached by pushing back one step from full pull, adjusts day, week, and moon phase. This eliminates the need for recessed correctors and tools.

Is this a limited edition?

While not officially numbered as a limited edition, the watch will have highly restricted production and is available exclusively through Audemars Piguet boutiques.

Source: Monochrome Watches – AP Royal Oak Perpetual Calendar Openworked 26685XT Review

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