Omega Speedmaster Professional “Moonwatch” | "Hesalite Sandwich" | Ref. 3572.50

The Omega Speedmaster Professional Ref. 3572.50 is one of the most interesting variations of the classic Moonwatch, often referred to by collectors as the “Hesalite Sandwich.” It combines the traditional Hesalite crystal on the front with a sapphire exhibition caseback, preserving the vintage appearance of the classic Speedmaster while allowing the movement to be viewed from the rear. The watch retains the familiar 42mm stainless-steel case, black dial, three-register chronograph layout, and black tachymeter bezel associated with the Speedmaster Professional.

Depending on its exact production point, the Ref. 3572.50 can be found with either the decorated Calibre 863 or the later rhodium-finished Calibre 1863. The Calibre 1863 is a manual-winding chronograph movement derived from the historic 861 architecture and was specifically finished for display through the sapphire caseback. This combination of Hesalite front crystal and exhibition back makes the 3572.50 particularly appealing to collectors who want the traditional Moonwatch experience while still being able to enjoy the movement.

Condition

Please review the photos carefully for an accurate representation. Light scratches, bracelet wear, bezel wear, Hesalite crystal wear, or other signs of use consistent with age may be present and do not affect functionality.

Based on the approximately 48.3-million serial range, we estimate this watch to date from the late 1990s (1997) This dating is an approximation only

Technical Data

• Reference: 3572.50 / 3572.50.00

• Model: Omega Speedmaster Professional Moonwatch

• Nickname: “Hesalite Sandwich” – Collector/Market Nickname

• Serial: Approximately 48.3M Range

• Case Diameter: 42mm

• Case Material: Stainless Steel

• Bezel: Black Tachymeter Bezel

• Dial: Black Speedmaster Professional Dial

• Crystal: Hesalite Front Crystal

• Caseback: Sapphire Exhibition Caseback

• Movement: Omega Calibre 1863

• Movement Type: Manual-Winding Chronograph

• Jewels: 18 for Calibre 1863

• Frequency: 21,600 vph / 3 Hz

• Power Reserve: Approximately 48 Hours

• Bracelet: Stainless-Steel Omega Bracelet

• Water Resistance: Originally rated to approximately 30 meters on many period specifications; current water resistance not guaranteed

• Functions: Hours, Minutes, Small Seconds, Central Chronograph Seconds, 30-Minute Counter, 12-Hour Counter & Tachymeter