1974 Omega Seamaster "PloProf" Ref.166.0077

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The Omega Seamaster Ref.166.0077 was nicknamed "PloProf" after an expression in French "Plongeur Professionel" which means professional diver. In fact, the nickname explains it all! This timepiece was designed to survive under extreme pressures water can create at the depth of up to 600 meters. The impressive monobloc case was cut out of single piece of stainless steel to increase waterproof capabilities. What appears to be the crown is actually a nut that releases and seals the actual crown, which is flat and square (!), sticking out when the tightening nut releases it. The bezel has a unique design and can only be rotated when the lock button is pressed. While Rolex and Doxa introduced gas escapement valves to fight the decompression, Omega found its' own way building the PloProf literally gas proof! All in all, it is a really impressive timepiece with unique design and capabilities.

This particular piece is notable for an exceptionally detailed case and an attractive and completely untouched dial and bezel in excellent condition.

Fully serviced in May 2018. Technical warranty: 1 year.


  • Mint stainless steel 1-piece monobloc case "Unishell"
  • Professionally detailed to Omega factory specs
  • 44 mm (without crown) / 50 mm (lug-to-lug) / 24 mm (between lugs)
  • Correct rotating bezel in mint condition showing two cracks at 5 and 6 o'clock
  • Original crowns and bezek lock button. 
  • Original mineral crystal in excellent condition
  • Reference: 166.0077


    • Automatic movement with date
    • In-house Cal.1001
    • Gold-plated, 20 Jewels, 28800 A/h, 42 hours of power reserve.
    • Good condition. Fully serviced in May 2018.


    • Original untouched blue dial in excellent condition
    • Signed "Omega Automatic" at 12 o'clock and "Seamaster 600 m / 2000 ft Professional" at 6 o'clock.
    • Original correct hands in excellent condition. Minor aging of tritium.

    Delivery set:

    • The watch with original Omega bracelet in good condition
    • Original Isofrane Omega rubber strap with Omega buckle
    • Our company’s warranty certificate, invoice and general terms and conditions.

    Collections: Archive

    Category: Omega

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    Sizing Product

    Measuring a watch

    It is always crucial to understand the size of the watch, especially when it comes to vintage watches which are generally considered as too small in comparison with what watch industry offers today. For example, the original Patek Philippe Calatrava introduced in the 1930s was only 31 mm in diameter, while today's classic Calatrava is 39 mm. When you think about 8 mm, it doesn't seem to be a big difference, but believe it is.

    In our condition reports we normally disclose three most important parameters as follows: diameter without crown / lug-to-lug length / lug width. 

    Diameter without crown

    It is, so far, the most important measurement to understand the size of a regular round-shaped watch.It helps you to understand proportions and overall look of the watch. It is important to consider width of the bezel and color of the dial, because certain combinations may make the watch look bigger, while some other smaller. It is all very individual, however there is common understanding:

    Lug-to-lug width

    This parameter will help you to understand whether the watch is comfortable for wearing. You should compare lug-to-lug width with the width of your wrist, and if lug-to-lug width is smaller or equal, then this watch shall be comfortable.

    Lug width

    This measurement is defining what size of strap you need for the particular watch. Depending on era and manufacturer you can find watches with lug width between 14 mm and 24 mm. Most common sizes are 18 mm and 20 mm.