Omega Seamaster Watch 600 Date - Calibre 613 Ref. 136.011/135.011 - Vintage 1968

Brand / Line
Omega Seamaster 600
Reference (case-back stamped)
135.011
(houses Cal. 613 date movement; the date variant is commonly catalogued as Ref. 136.011)*
Movement
Omega Calibre 613 – 17-jewel, manual-wind, quick-set date, ≈19 800 A/h
Serial Nº
26 37 3 562 (circa 1968)
Case
Solid stainless steel, ≈34 – 34.5 mm width (ex-crown), 18 mm lug width
Dial
Factory black, applied steel indexes & logo, date at 3 o’clock
Crystal
Acrylic (signed Ω)
Crown
Original signed Ω, push-pull
Case-back
Screw-in, hippocampus logo (lightly polished)
 
Water resistance
Not pressure-tested – sold as vintage collectible
Condition
Running well, date advances correctly; light case marks from age; dial & hands very clean; service history unknown