Zenith · ref A3642 · from 1969 into the 1970s
The Defy arrived in 1969, the same year as the El Primero, and Zenith billed it as Il casaforte del tempo, the safe of time. The A3642 was the first one. Its 37mm steel case is an eight-sided shape collectors call the Miura case, topped with a fourteen-sided bezel, and it was water resistant to 300m without saying so on the dial. Zenith mounted the movement in a rubber ring inside a capsule case to soak up shocks. Early watches run the cal. 2552 PC, a 23-jewel automatic with date at 21,600 beats an hour, and from the early 1970s Zenith switched to the faster 2562 PC and printed 28,800 on the dial. It came on Gay Frères' ladder bracelet, which is an acquired taste. The brown-to-black gradient dial is the one you'll see most. Zenith reissued it as the Defy Revival A3642 in 2022, so check you're getting the 1969 watch.
The caliber
The Defy runs Zenith's in-house 25-series automatics. The cal. 2552 PC beats 21,600 times an hour with 23 jewels, a date and about 46 hours of reserve, and the earlier 2542 PC belongs to the same family. In the early 1970s the 2562 PC raised the beat to 28,800, and Zenith printed that number on Defy dials, which helps you date a watch at a glance.
Polishing softens the sharp facets that make the Defy, and ladder bracelets often haven't held up well over the decades. Modern Revival models also get listed next to vintage ones.
Buying guide
We'd buy the A3643 titled unpolished, on a Gay Frères bracelet, at $2,255 delivered from the US, in the lower half of the band. Few titles name the A3642 itself, so this page pools about 25 of its 1969–71 siblings like the A3643, A3645 and A7682, and most ask $1,675–3,700 delivered, with orange-dial A3648s and Gauss models at $3,600–6,600. Look for 28,800 printed on the dial, which means an early-1970s 2562 PC, sharp facets on the case and bezel in the side photos, and a solid back, since a display back is the 2022 Revival. Check the seller's feedback and return policy on the item page, since eBay's watch search doesn't show them, and expect import costs on most, which ship from Italy, Argentina and elsewhere outside the US.
$1,207.70est. delivered
The lowest ask on a Defy titled working, an A3645 with a black dial at $1,208 delivered from the UK, about $470 under the band. Ask for a movement photo and a side view of the case to check the facets.
Vintage Zenith Defy A3645 Black Dial Automatic 1970s - Working
$2,255.27est. delivered
An A3643 titled unpolished, on a Gay Frères bracelet, at $2,255 delivered from the US, so there's no import duty to add. Unpolished is the seller's word, so check that the case and bezel facets look sharp in the side photos.
Zenith Defy Octagonal Vintage UNPOLISHED A3643 Gay Freres Bracelet
$3,524.00est. delivered
The only Defy here titled with a service, at $3,524 delivered from Argentina, near the top of the band. The 28800 in the title is the beat rate printed on later dials, so expect a 2562 PC and ask what the service covered.
Zenith Defy vintage ref 28800 year 1970 with service
Delivered prices include shipping as eBay quoted it to a US address on Oct 6, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Snapshot
Checked . Some may have sold.
Delivered prices include shipping as eBay quoted it to a US address on Oct 6, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Used$1,207.70est. delivered
$1,138.71 + $68.99 shipping
Buy It Now$1,138.71
Good buy
A3645, black dial, 1970s, titled working. Ships from the UK.
Seller: Seller on eBay
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Used$2,255.27est. delivered
$2,250.00 + $5.27 shipping
Buy It Now$2,250.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
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Good buy
A3643, titled unpolished, on a Gay Frères bracelet.
Seller: Seller on eBay
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Serviced$3,524.00est. delivered
$3,490.00 + $34.00 shipping
Buy It Now$3,490.00
This seller takes offers, and many sellers accept less than the asking price.
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Good buy
No reference given. Titled 1970, with service. Ships from Argentina.
Seller: Seller on eBay
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Used$1,727.65est. delivered
$1,677.00 + $50.65 shipping
Buy It Now$1,677.00
This seller takes offers, and many sellers accept less than the asking price.
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Our take
No reference given. Cal. 2552 PC on a Gay Frères bracelet. Ships from Italy.
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Used$2,042.79est. delivered
$1,969.63 + $73.16 shipping
Buy It Now$1,969.63
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
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Our take
No reference given. Sub Sea dial, cal. 2562 PC. Ships from Italy.
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Used$2,400.00delivered
$2,400.00 · free shipping
Buy It Now$2,400.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
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Our take
No A-number reference. Titled cal. 2552 PC, octagonal case. Ships from Argentina.
Seller: Seller on eBay
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Used$2,250.00est. delivered
$2,200.00 + $50.00 shipping
Buy It Now$2,200.00
Check the seller
A7682 with the 2562 PC. The same title is also listed from Venezuela at $1,250, so ask which watch this is.
Seller: Seller on eBay
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Used$6,620.00est. delivered
$6,500.00 + $120.00 shipping
Buy It Now$6,500.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Priced high
A3648, about $2,900 over the band. Ships from Australia.
Seller: Seller on eBay
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Prices change daily. The live eBay search shows everything listed now, including anything new since Oct 6, 2026.
See every listing on eBay ↗eBay searchA fresh strap, a set of spring bars and a spring-bar tool are the cheap part of making an old Zenith Defy A3642 wearable again. This searches Amazon for the usual kit.
Search straps & tools ↗Amazon search
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