Rolex Explorer II 16570 'Panna Dial' 40MM 1991

Rolex Explorer II 16570 ‘Panna Dial’ 40MM 1991

Produced between 1989 and 2011, the Rolex Explorer II 16570 represents the longest running reference in the Explorer II lineage and a significant evolution of Rolex’s dual time sports watch. An early 1990s example featuring what is now known as a ‘Panna’ dial occupies a particularly compelling position within that production span. With its balanced 40mm case, independent 24 hour hand and tritium dial that has aged into a warm cream tone with pumpkin patina, this configuration reflects both the functional origins of the model and the natural character that develops over time.

The Origins of the Explorer II

From Cave Exploration to Dual Time Function

The Explorer II was introduced in 1971 as a specialist tool watch designed for cave explorers, polar adventurers and those operating in environments where natural light was limited. Unlike the Submariner, which was built for divers, or the GMT Master, which was developed for pilots, the Explorer II served a distinct purpose.

The original reference 1655 featured a fixed 24 hour bezel and a bold orange 24 hour hand, allowing the wearer to distinguish between day and night in conditions where sunrise and sunset were not easily perceived. The bezel was engraved rather than rotating, reinforcing the watch’s focus on stability and clarity rather than multiple adjustable time zones.

The Transition to 40mm and Sapphire

In the mid 1980s, Rolex introduced the reference 16550, which marked a major evolution. The case grew to 40mm, sapphire crystal replaced acrylic and the 24 hour hand became independently adjustable. This was the technical foundation upon which the 16570 would build.

The 16570 as a Refined Successor

Consolidating the Platform

When the 16570 was introduced, Rolex retained the 40mm Oyster case and fixed steel bezel while refining the movement and improving reliability. Early 1990s examples were fitted with tritium dials marked “Swiss – T < 25,” reflecting the luminous material used at the time.

The reference maintained its core identity as a practical sports watch. There were no rotating bezels in contrasting colours and no precious metal centre links. The Explorer II remained understated, functional and purpose driven.

The Emergence of the ‘Panna’ Dial

Within early production white dial examples, a transformation occurred over time. Certain dials aged from bright white into a creamy tone, now widely referred to as ‘Panna.’ This change is the result of ageing in the dial lacquer and tritium compound rather than a factory variation.

The Panna effect is subtle but distinctive. Instead of stark white contrast against the steel case, the dial develops warmth and depth, softening the overall appearance of the watch.

The Aesthetic of Organic Ageing

Cream Dial and Pumpkin Patina

The defining characteristic of a Panna dial 16570 is the shift from bright white to cream. The ageing process varies between examples, giving each watch a unique visual signature.

The tritium hour markers typically develop a pumpkin patina, transitioning to a warm amber tone. When the hands age in harmony with the markers, the dial appears cohesive and balanced. The contrast between cream dial, black surrounds and brushed steel bezel creates depth without excess.

Material Reality of the Early 1990s

In the early 1990s, tritium was standard across the range. Later service or replacement dials using Luminova do not age in the same manner. The Panna dial therefore reflects a specific material era within Rolex production history.

Case Proportions and Functional Identity

The 40mm Oyster Case

The 40mm Oyster case of the 16570 is notably restrained when compared to later six digit references. The lugs are slimmer, the profile more tapered and the overall thickness moderate. The watch wears flatter and more balanced than modern interpretations.

The fixed 24 hour bezel, engraved and black filled, reinforces the utilitarian nature of the model. The brushed finish across the bezel and upper case surfaces reduces glare, aligning with the watch’s intended use in snow, ice or harsh light conditions.

Drilled Lug Heritage

Early 1990s examples often feature drilled lug holes, a detail that underscores the tool watch roots of the reference. This construction simplifies strap changes and reinforces the watch’s practical origins.

Movement and Technical Foundation

Calibre 3185

At the heart of early 16570 examples is the Rolex Calibre 3185. This automatic movement operates at 28,800 vibrations per hour and incorporates an independently adjustable 24 hour hand.

This function allows the wearer to track a second time zone without disturbing the primary time display. The quickset date mechanism enables efficient adjustment when travelling.

The movement features a free sprung balance regulated by Microstella screws and a full balance bridge for enhanced shock resistance. In the context of its era, the 3185 represented a robust and technically sound platform.

Position Within the Explorer Line

Explorer I Versus Explorer II

While the Explorer I focuses on time only simplicity, the Explorer II adds practical complication. The 16570 preserves the clarity and legibility associated with the Explorer name while offering dual time functionality.

The Panna dial does not change the architecture of the watch. Instead, it adds nuance and visual warmth to an otherwise highly utilitarian design.

Early 1990s Rolex Context

Incremental Refinement

The early 1990s marked a period of stability for mechanical watchmaking. Rolex continued its strategy of incremental refinement rather than radical redesign.

Sapphire crystals, improved case tolerances and reliable automatic movements characterised the era. The 16570 fits squarely within this philosophy. It was not reinvented. It was strengthened and perfected.

Bracelet and Wearability

Oyster Bracelet

The Explorer II 16570 was typically paired with the Oyster bracelet, reference 78360 in early production. The three link construction complements the watch’s tool aesthetic, with brushed outer surfaces that align with the case and bezel finishing.

On the wrist, the 40mm diameter offers presence without excess. The balanced lug to lug length and moderate thickness ensure comfort across a wide range of wrist sizes.

Why We Love the Panna Dial 16570

Atmosphere and Character

What sets the Panna dial apart is the atmosphere it creates. The cream dial introduces warmth to a watch defined by steel and black engraving. The pumpkin patina adds depth and visual richness.

This ageing is not artificial or decorative. It is the result of time interacting with material. The dial becomes a record of decades rather than a static surface.

Function First, Always

Despite the aesthetic evolution, the Explorer II remains fundamentally a tool watch. The independent 24 hour hand, fixed bezel and robust Oyster case preserve its original intent. The Panna dial enhances the story without altering the function.

Final Thoughts

The Rolex Explorer II 16570 ‘Panna Dial’ 40mm from the early 1990s represents the intersection of purposeful engineering and organic ageing. Produced during a period of technical consolidation, it combines sapphire crystal, the Calibre 3185 movement and the enduring Oyster architecture.

The cream dial and pumpkin patina are natural developments within the tritium era, adding warmth and individuality to a fundamentally utilitarian design. Balanced proportions, fixed bezel functionality and mechanical robustness define the reference. The Panna dial does not redefine the Explorer II. It deepens it, reinforcing the enduring clarity and purpose that have characterised the model since its introduction.

• Case in great vintage condition, light hairlines visible.
• Lugs very sharp with factory brushing still visible.
• Bracelet in great vintage condition, hairline scratches visible.

• Dial & hands have formed pumpkin patina
• Dial has aged into a cream colour