Source: Images and content by Rolex. See the original article here - https://newsroom.rolex.com/watches/oyster-collection/explorer-ii
The Explorer II is an extremely legible watch in all circumstances. The sleek, high-contrast dial is easy to read even in the dark thanks to the Chromalight display; the hour markers and hands are filled or coated with a luminescent material emitting a long-lasting blue glow – for up to two times longer than traditional phosphorescent materials. This display has been further optimized: from 2021, the blue glow is emitted at the same intensity for even longer.
THE EXPLORER II, A SUPERLATIVE CHRONOMETER CERTIFIED
Like all Rolex watches, the Explorer II is covered by the Superlative Chronometer certification redefined by Rolex in 2015. This exclusive designation attests that every watch leaving the brand’s workshops has successfully undergone a series of tests conducted by Rolex in its own laboratories and according to its own criteria. These certification tests apply to the fully assembled watch, after casing the movement, guaranteeing superlative performance on the wrist in terms of precision, power reserve, waterproofness and self-winding. The Superlative Chronometer status is symbolized by the green seal that comes with every Rolex watch and is coupled with an international five-year guarantee.
The precision of every movement – officially certified as a chronometer by the Swiss Official Chronometer Testing Institute (COSC) – is tested a second time by Rolex after being cased, to ensure that it meets criteria that are far stricter than those of the official certification. The precision of a Rolex Superlative Chronometer is of the order of −2/+2 seconds per day – the rate deviation tolerated by the brand for a finished watch is significantly smaller than that accepted by COSC for official certification of the movement alone.
The Superlative Chronometer certification testing is carried out after casing using state-of-the-art equipment specially developed by Rolex and according to an exclusive methodology that simulates the conditions in which a watch is actually worn and more closely represents real-life experience. The entirely automated series of tests also checks the waterproofness, the self-winding capacity and the power reserve of 100 per cent of Rolex watches. These tests systematically complement the qualification testing upstream during development and production, in order to ensure the watches’ reliability, robustness, and resistance to magnetic fields and shocks.
THE OYSTER CASE, SYMBOL OF WATERPROOFNESS
The Explorer II’s Oyster case, 42 mm in diameter and guaranteed waterproof to a depth of 100 metres (330 feet), is a paragon of robustness and reliability. The middle case is crafted from a solid block of Oystersteel, a particularly corrosion-resistant alloy. The case back, edged with fine fluting, is hermetically screwed down with a special tool that grants only Rolex watchmakers access to the movement. The Twinlock winding crown, fitted with a double waterproofness system and protected by a crown guard that is an integral part of the middle case, screws down securely against the case. The crystal, with a Cyclops lens at 3 o’clock for easy reading of the date, is made of virtually scratchproof sapphire. The waterproof Oyster case provides optimum protection for the Explorer II’s movement.
PERPETUAL CALIBRE 3285
The Explorer II is equipped with calibre 3285, a self-winding mechanical movement entirely developed and manufactured by Rolex. A consummate demonstration of technology, this movement carries a number of patents. It offers outstanding performance in terms of precision, power reserve, resistance to shocks and magnetic fields, convenience and reliability.
The oscillator of calibre 3285 has a large balance wheel with variable inertia regulated extremely precisely via gold Microstella nuts. It is held firmly in place by a height-adjustable traversing bridge enabling very stable positioning to increase shock resistance. The oscillator is also fitted on high-performance Paraflex shock absorbers, designed and patented by Rolex.
Calibre 3285 features an optimized version of the blue Parachrom hairspring, manufactured by Rolex in a paramagnetic alloy. Insensitive to magnetic fields, the Parachrom hairspring offers great stability when exposed to temperature variations and remains up to 10 times more precise than a traditional hairspring in case of shocks. It is equipped with a Rolex overcoil, guaranteeing its regularity in any position.
This calibre incorporates the Chronergy escapement, made of nickel-phosphorus and patented by Rolex, which combines high energy efficiency with great dependability and is also insensitive to magnetic fields.
Calibre 3285 is fitted with a self-winding module featuring a Perpetual rotor, which ensures continuous winding of the mainspring by harnessing the movements of the wrist to provide constant energy. Thanks to its barrel architecture and the escapement’s superior efficiency, the power reserve of this movement extends to approximately 70 hours.
The Explorer II’s movement will be seen only by certified Rolex watchmakers, yet it is beautifully finished and decorated in keeping with the brand’s uncompromising quality standards.
BRACELET AND CLASP, SECURE AND COMFORTABLE
The Explorer II is available on a three-piece link Oyster bracelet. This bracelet is equipped with an Oysterlock safety clasp, designed and patented by Rolex, which prevents accidental opening. It is additionally fitted with the Easylink comfort extension link, developed by the brand, which allows the wearer to easily increase the bracelet length by approximately 5 mm, for additional comfort in any circumstance. A concealed attachment system ensures seamless visual continuity between the bracelet and case.