Case
Model: Rolex Day-Date 40
Reference: 228235
Case Size: 40 mm diameter
Case Material: 18 ct Everose gold — not Everose Rolesor
Case Thickness: Approximately 12 mm
Lug Width: Approximately 20 mm
Water Resistance: 100 meters / 330 feet
Crown: Screw-down Twinlock double waterproofness system
Caseback: Solid, screw-down Oyster caseback
Oyster Architecture: Monobloc middle case with screw-down caseback and winding crown
Rolex officially specifies the case as an Oyster, 40 mm, entirely in 18 ct Everose gold.
Bezel
Type: Fluted
Material: 18 ct Everose gold
Function: Decorative, non-rotating
The standard 228235 is specified by Rolex with a fluted bezel. Some 228235 configurations can have gem-set bezels, but a smooth Oystersteel bezel is not applicable because the watch is entirely 18 ct Everose gold.
Crystal
Type: Scratch-resistant sapphire crystal
Cyclops: Yes, Cyclops lens over the date
Anti-reflective coating: Yes, on the underside of the crystal
Movement
Calibre: Rolex Calibre 3255
Type: Perpetual, mechanical, self-winding
Winding: Bidirectional self-winding via Perpetual rotor
Frequency: 28,800 vibrations/hour (4 Hz)
Jewels: 31
Power Reserve: Approximately 70 hours
Manufacture: Manufacture Rolex
Escapement: Chronergy escapement
Rolex specifically identifies calibre 3255 as the movement used in the Day-Date 40 and gives its power reserve as approximately 70 hours.
Functions
Hours
Minutes
Seconds
Instantaneous day and date
Day displayed through the 12 o’clock aperture
Date displayed through the 3 o’clock aperture
Rapid-setting day and date
Stop-seconds mechanism for precise time setting
The day display is an important difference from your supplied specifications: reference 228235 is a Day-Date, so it displays both the day and date.
Oscillator / Balance
Hairspring: Blue Parachrom paramagnetic hairspring
Escapement: Chronergy escapement
Balance Wheel: Variable-inertia balance with Microstella regulation
Shock Protection: High-performance Paraflex shock absorbers
Overcoil: Rolex overcoil
The 228235 does not use the Syloxi silicon hairspring. The calibre 3255 uses Rolex’s blue Parachrom hairspring.
Dial
Available configurations vary by production year and specific suffix/reference configuration. Examples include:
Sundust
Chocolate
White
Slate
Olive green
Mother-of-pearl
Diamond-set dials
Various Roman numeral, baton and gem-set configurations
Hour markers can be applied Roman numerals, baton markers, or diamond/gem-set markers depending on the specific dial.
The exact dial should therefore be specified using the full reference, such as 228235-0001, rather than just 228235. For example, Rolex lists 228235-0001 with a Sundust dial and Roman numerals.
Bracelet
Bracelet Type: President
Construction: Semi-circular three-piece links
Material: 18 ct Everose gold
Clasp: Concealed folding Crownclasp
Ceramic Inserts: Rolex patented ceramic inserts are incorporated into the bracelet links to improve flexibility and longevity
The President bracelet is the defining bracelet for the Day-Date and is not an Oyster or Jubilee bracelet on the standard 228235.
Certification
Certification: Superlative Chronometer
Official chronometer certification: COSC
Rolex certification: Additional Rolex testing after casing
Accuracy: −2 / +2 seconds per day, after casing
Water Resistance: 100 m / 330 ft
Warranty
Rolex International Warranty: 5 years from the date of purchase for watches sold under Rolex’s current five-year warranty policy.