Model guide · Seamaster
Vintage Omega Ploprof 600: the 166.077, its calibre and value
The Seamaster 600 "Ploprof" is Omega's professional dive watch of the 1970s, rated to 600 metres and built like a piece of diving equipment. There is one vintage reference, and one calibre in it. Here is how to know you are looking at a real one, and what it's worth.
Find one on eBay
Live listings and real sold prices for the Ploprof, its big brother and its parts.
The photos to ask a seller forAffiliate links: Watch Breaker may earn a small commission. Opens in a new tab.
What the Ploprof is
The name is short for plongeur professionnel, professional diver. Omega built it for commercial divers working at depth, and it is rated to 60 bar, 600 metres, five times the depth of the Seamaster 120 and twice that of the Seamaster 300. Omega's database lists it from 1970 through the decade. Omega brought the name back in 2009 on a modern 1,200-metre watch, so when you search for one, make sure what you are looking at is the vintage 166.077.
How to identify one
Case: a single block of steel with no caseback, about 55 mm across and 13.5 mm thick. Omega calls it a unishell: the movement goes in and out through the front. Bezel: it locks, and a push-button on the side of the case releases it so it can't be knocked off a dive time. Crown: under a heavy screw-down guard. Dial and hands: most have a black dial with a large orange minute hand. Strap: Omega's database lists an Isofrane rubber strap; Omega's steel mesh bracelet was the other original fitting.
| Reference | Years | What it is | Calibre | Rated | Case |
|---|---|---|---|---|---|
| ST 166.0077 | 1970–1979 | Seamaster 600 "Ploprof" | 1002 | 600 m | Unishell, opens from the dial side, 55 × 13.5 mm |
| ST 166.0093 | 1972 | Seamaster 1000, its deeper sibling | 1002 / 1012 | 1,000 m | Screw-in back, steel bracelet |
Source: Omega's vintage database, as held in the reference lookup, which writes the reference as 166.0077. Most sellers list it as 166.077. Some published references give the 1001 for the Ploprof; Omega's database gives the 1002.
The calibre 1002, from the factory catalogue
Omega's GF 620-5 spare-parts catalogue lists the 1002 as 27,90 RA SC PC CAL CORR INST STS 20 pierres. Decoded, that is a 27.90 mm movement (27,90), automatic winding (RA, remontage automatique), centre seconds (SC), shock protection (PC, pare-chocs), a date (CAL, calendrier) with instant correction (CORR INST), stop-seconds (STS) and 20 jewels. It belongs to the 1000 family Omega introduced in 1969. The 1001 is the same movement with a chronometer certificate (BULL, for bulletin), and the 1000 is the 17-jewel base. The calibre lookup has all three.
Is your Ploprof all original?
The reference, the calibre and the dial have to agree. Six photos and the weight, and I check them against Omega's own records and put it in writing. Nothing to pay until I confirm the photos can answer it.
Dating one
The serial is on the movement, and on a unishell case that means opening the watch from the front to read it. The serial number lookup gives the year band, which should land in the 1970s. A seller who can't show the movement can't prove the date, and that should be reflected in the price.
What it's worth
An honest vintage 166.077 sells for several thousand dollars. Where it lands in that range is set by originality: the dial, the hands and the bezel insert it left the factory with, and whether it still has an original strap or mesh bracelet. Replacement parts fitted at service are genuine Omega but lower the collector price. Use the "What they sold for" links above to see real prices. What's my Omega worth? explains the parts and gold values too.
What goes wrong with them
Service parts. Bezels, crystals, hands and dials were replaced at service, and the lume will often not match across them. Missing strap or bracelet. An original Isofrane or mesh adds real value, and sellers know it, so reproductions are common. The unseen movement. Because the case opens from the front, the movement is rarely photographed and can be anything. Water. Treat a fifty-year-old dive watch as not water-resistant until the case has been pressure-tested.
Buying one without getting burned
Before you pay, ask for these photos:
- The dial and hands, square on and in daylight. The lume should match in colour and age.
- The bezel and its release button. The bezel should turn only with the button pressed.
- The back of the case. A plain block, with no caseback to unscrew.
- The movement, if the seller has had it open. A 1002 with its serial readable.
- The strap or bracelet, close up. Original fittings are signed.
Six photographs and the weight, and I put it in writing: calibre confirmed against its factory sheet, case checked against Omega's own case data, serial dated, dial judged, three honest values. Within a day. US$75, and nothing to pay until I confirm the photos can answer it.
Questions people ask
What does Ploprof mean?
It is short for plongeur professionnel, French for professional diver. Omega built it for commercial divers and rated it to 600 metres, far deeper than any other Seamaster of its time.
What movement is in a vintage Omega Ploprof?
Omega's vintage database lists the calibre 1002 for the 166.0077: a 27.90 mm automatic with date, instant date change, stop-seconds and 20 jewels, from the 1000 family introduced in 1969. The 1001 is the chronometer-certified version of the same movement.
How do I open a vintage Ploprof?
From the front. The case has no caseback, so the movement comes out through the dial side once the crystal and bezel are off. That is why listings rarely show the movement, and why it should only be opened by someone with the right tools.
How much is a vintage Omega Ploprof worth?
An honest 166.077 sells for several thousand US dollars. Originality decides where in that range: the dial, hands and bezel it left the factory with, and whether it still has an original strap or mesh bracelet. Check the sold prices on this page rather than asking prices.
Watch Breaker is an independent identification specialist and parts dealer and is not affiliated with, endorsed by or connected to Omega SA or the Swatch Group. Omega is a trademark of Omega SA. Reference data is from Omega's vintage database; calibre data is transcribed from Omega's GF 620-5 catalogue. Terms.