CALIBER/browser
CORPUS EXPORT · 12269 calibers · 59387 family views · round round/2026-09-08Compiled from app/public/data/ · corpus 70c0140eba.
Family treeETA 2551 — Heritage family: 11 calibers, 10 sourced lineage links.Drag to explore.
100%drag to pan · hover a caliber to isolate its line · scroll the page normallyopen the full family view →
ébauche ofébauche ofébauche ofébauche ofébauche ofébauche ofébauche ofébauche ofébauche ofébauche ofDugena 1019 (ETA 2551) — open caliber pageDugena 1019 (ETA 255…1965maker not sourced1 exec · grade ?Dugena 1081 (ETA 2551) — open caliber pageDugena 1081 (ETA 255…1965maker not sourced1 exec · grade ?Dugena 3309 (ETA 2551) — open caliber pageDugena 3309 (ETA 255…1965maker not sourced1 exec · grade ?Enicar 765 (ETA 2551) — open caliber pageEnicar 765 (ETA 2551)—maker not sourc…1 exec · grade ?ETA 2551 — the caliber this page is aboutETA 25511965ETA SA Manufacture Horlogère…1 exec · grade ?Girard-Perregaux 82.0 (ETA 2551) — open caliber pageGirard-Perregaux 82.0 (ETA 2…1965maker not sourced1 exec · grade ?Hamilton 79 (ETA 2551) — open caliber pageHamilton 79 (ETA 2551)—maker not sourc…1 exec · grade ?MST 473 (ETA 2551) — open caliber pageMST 473 (ETA 2551)—maker not sourc…1 exec · grade ?Tissot 744 (ETA 2551) — open caliber pageTissot 744 (ETA 255…1967maker not sourced1 exec · grade ?Tissot 764 (ETA 2551) — open caliber pageTissot 764 (ETA 255…1968maker not sourced1 exec · grade ?Tissot 766 (ETA 2551) — open caliber pageTissot 766 (ETA 255…1968maker not sourced1 exec · grade ?
accepteddisputed
Sense of “family”Heritage · 11Everything (debug) · 11Parts cluster (Jules Borel sense) · 1Manufacturer-internal (Ranfft sense) · 1Based-on star (WatchBase sense) · 11Open the full family view →

movement

ETA 2551

ETA SA Manufacture Horlogère Suissearchive filingintroduced 1965design:eta-2551compare specs · 8
bounding evidence — no range is drawn on the era axis
not after 1970
a dated example movement, 1970“1970: 12608399, Chs. Tissot & Fils, Swiss, 21 Jewels - Patented; Incabloc”

Identity

A caliber is three separate things and this reference keeps them apart: the construction, the names it is sold under, and the article a brand actually bought. A watch model points at an execution — never at a bare construction — which is why “same caliber” is almost never a complete answer.

IDesign — the construction
ETA 2551
movementproducer: ETA SA Manufacture Horlogère Suissearchive filing
IIDesignations — 0 names

No designation is recorded for this design yet.

IIIExecutions — 1 article

No source in this corpus states which grade any ETA 2551 was bought at. That unknown is stored as a real row rather than left blank, so it can be counted, filtered and excluded from any comparison that would otherwise assume parity.

unknownsynthetic
evidence: unknown

no source states which grade this article was bought at — this row exists so 'unknown' stays countable instead of becoming an assumption

exec:eta-2551/unknown

Specifications

PropertyValueScopeStatusSources
Jewels
build.jewel_count
21—accepted
Jewels
build.jewel_count
17Ranfft data sheet, the 17-jewel member of its 17/21/23 rangeaccepted
Jewels
build.jewel_count
21Ranfft data sheet, the 21-jewel member of its 17/21/23 rangeaccepted
Jewels
build.jewel_count
23Ranfft data sheet, the 23-jewel member of its 17/21/23 rangeaccepted
Date correction
disp.date_quickset
none—staged
Date
disp.has_date
yes—staged
Seconds display
disp.seconds_display
central—staged
Lift angle
esc.lift_angle_deg
51 deg—accepted
Casing diameter
geom.casing_diameter_mm
17.5 mm—staged
Movement diameter
geom.diameter_mm
17.2 mm—staged
Movement height
geom.height_mm
4.5 mm—accepted
Movement height
geom.height_mm
4.65 mm—accepted
Swiss movement
origin.swiss_movement
yes—accepted
Frequency
osc.frequency_vph
21600 vph—accepted
Shock protection
osc.shock_protection
incablocexample movement, 1970staged
Power reserve (typical)
power.reserve_typical_h
42 h—accepted
Discontinued
prod.discontinued_year
1972—staged
Introduced
prod.intro_year
1965—staged
Winding direction
wind.direction
bidirectional—accepted
Hacking seconds
wind.has_hacking_seconds
no—accepted
Quickset date
wind.has_quickset_date
yes—accepted
Winding mode
wind.mode
automatic—accepted

Where a property carries more than one value, the values have different scopes — an official spec sheet and observed hardware, say. Different scopes are not a disagreement, so both are accepted and both are shown with the scope they apply to.

Lineage

The same relationships as the tree at the top of this page, with their sources. An absence in a column means no source stated one.

Ancestors · 0

Where this construction came from. Read up the arrows.

None recorded. An absence here means no source stated one, not that none exists.

Related · 0

Stored in a different table from descent. A successor is not a child.

None recorded. An absence here means no source stated one, not that none exists.

Sources

  1. 1
    Internet Archive
    https://web.archive.org/web/20181107094137/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&ETA_2551
    archivetier 2retrieved 2018-11-0717 facts on this page
  2. 2
    Caliber Corner
    https://calibercorner.com/eta-caliber-2551
    curated dbtier 2retrieved 2026-09-0810 facts on this pagecited, never crawled
  3. 3
    Internet Archive
    https://web.archive.org/web/20181106132012/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&Dugena_1019
    archivetier 2retrieved 2018-11-061 fact on this page
  4. 4
    Internet Archive
    https://web.archive.org/web/20190820100933/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Dugena_1081
    archivetier 2retrieved 2019-08-201 fact on this page
  5. 5
    Internet Archive
    https://web.archive.org/web/20181106134349/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&Dugena_3309
    archivetier 2retrieved 2018-11-061 fact on this page
  6. 6
    Internet Archive
    https://web.archive.org/web/20181106152631/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&Enicar_765
    archivetier 2retrieved 2018-11-061 fact on this page
  7. 7
    Internet Archive
    https://web.archive.org/web/20181107153925/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&Girard-Perregaux_82_0
    archivetier 2retrieved 2018-11-071 fact on this page
  8. 8
    Internet Archive
    https://web.archive.org/web/20191114084847/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Hamilton_79
    archivetier 2retrieved 2019-11-141 fact on this page
  9. 9
    Internet Archive
    https://web.archive.org/web/20230901184503/http://ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&MST_473
    archivetier 2retrieved 2023-09-011 fact on this page
  10. 10
    Internet Archive
    https://web.archive.org/web/20181108074230/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&Tissot_744
    archivetier 2retrieved 2018-11-081 fact on this page
  11. 11
    Internet Archive
    https://web.archive.org/web/20230902001505/http://ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Tissot_764
    archivetier 2retrieved 2023-09-021 fact on this page
  12. 12
    Internet Archive
    https://web.archive.org/web/20230902001525/http://ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Tissot_766
    archivetier 2retrieved 2023-09-021 fact on this page