Mido Ocean Star Decompression Timer

Produced from the late 1950s and officially launched in 1961, this timepiece dedicated to underwater pursuits is a valuable tool for divers, thanks to the multicoloured display of the decompression stages on its dial and its rotating bezel. It can also be found under other names, such as Ocean Star Rainbow Diver or Ocean Star Powerwind 1000.

In a real-life deep diving situation, the watch shows the diver whether a decompression period has to be observed when reascending, and specifying the duration of each stage. This feature, which was an incredible innovation at the time, was the result of in-depth research undertaken in conjunction with renowned divers from across the world. 


Close up

At this time, cases were usually made in three sections, but Mido developed a case made as a single piece, known as a "monocoque" case. Guaranteeing superior water resistance, this world first eliminated one of the three crucial water ingress points found in standard watch constructions at the time, namely the case back. Each watch was tested at a pressure corresponding to a depth of 300 metres and was guaranteed to be 100% water-resistant at this depth.

The legendary monocoque case has been constantly in production since 1959 and still exists today on the brand's current models. This invention, and that of the Aquadura system, secured the brand's fame as the "King of Waterproof" watches at the time.

Technical drawing

What do you know about the Aquadura system? 

From 1934 until a few years ago, this unique system proved its worth by protecting the precious mechanisms inside Mido watches from water. The highly innovative gasket system provides the watch with almost total water resistance. It uses natural cork which has been specially treated and which seals the crown winding stem, a weak point on all watches. By forming a perfect seal around the crown winding stem, Mido guarantees complete water resistance even if the crown is not pushed fully back in. 

Technical specs:

  • Exclusively for Mido using the AS 1131/1132 as a base 
  • Specially for Ocean Star
  • Option: Fonto regulator with mobile stud support and adjustable regulator arbor width
  • Mido Limited, Switzerland, 17 jewels, Incabloc