Vintage Eterna-Matic Kontiki 20 Watch Day/Date 37mm ALL S.S. - Original Bracelet

Watch Overview

ETERNA-MATIC Watch Co. — “First gents automatic-family with ball-bearing rotor”.

Offered here is a collectible vintage Eterna-Matic KonTiki 20 automatic wristwatch, dating from the 1970s.

The Eterna-Matic movement system, introduced by Eterna in 1948, became one of the brand’s most important innovations. It utilized five strategically placed ball bearings to support the automatic winding rotor, significantly reducing friction and improving winding efficiency while minimizing wear on internal components. This innovation became so influential that the five-ball-bearing logo remains part of Eterna’s identity today.

The KonTiki line was inspired by Thor Heyerdahl’s famous 1947 Kon-Tiki expedition across the Pacific Ocean. Eterna supplied watches for the journey, and the success of the expedition helped establish the model name as one associated with durability. By the 1970s, models such as the KonTiki 20 blended robust automatic movements with modern case design.

It is powered by the Eterna-Matic automatic movement caliber ETA 2836, featuring 25 jewels, a sweep seconds hand, and a quick-set day-date display. This Swiss-made movement operates at 28,800 vph and offers an approximate 40-hour power reserve.

The watch features a light silver-green dial accented by applied baton hour markers, printed minute track, luminous plots, and matching baton hands. The day-date display is positioned at 3 o’clock.

Housed in a 37mm stainless steel tonneau-style case with a fixed smooth bezel and signed KonTiki caseback medallion. It is fitted with its original stainless steel bracelet.

Fully inspected and authenticated, the watch remains in very good vintage condition consistent with its age and is ready to wear and enjoy.

Product Details

General Specifications

• Brand: Eterna-Matic
• Type: Wristwatch
• Model: KonTiki 20
• Year / Era: 1970s – Vintage
• Gender: Men's
• Country of Manufacture: Switzerland

Dial & Display

• Display: Analog
• Dial Color: Light Silver-Green
• Features: Baton hour markers, minute track, sweep-seconds hand, day/date indicator

Movement

• Movement Type: Automatic / Self-Winding
• Caliber: ETA 2836
• Jewels: 25 Jewels
• Movement Functions:
  • Sweep seconds
  • Quick-set day/date display
  • Eterna-Matic ball-bearing rotor system
• Power Reserve: Approx. 40 Hours
• Frequency: 28,800 vph

Case & Band

• Case Material: Stainless Steel
• Case Shape: Tonneau / Barrel
• Bezel: Fixed, Smooth
• Case Back: Screw-Back
• Bracelet: Original Stainless Steel Bracelet
• Max Wrist Size: Approx. 8"

Case Measurements (mm)

• Case Size: 37
• Case Diameter w/Crown: 40
• Case Lug to Lug: 42
• Case Thickness: 11.7
• Band Width: 25.4

Additional Info

• Box & Papers: No
• Condition: The watch is in very good vintage condition, showing signs of wear consistent with age and normal use.
• Notes: Fully inspected and authenticated by our in-house watchmaker. Ready to wear.

About Second Hand Horology

At SECOND HAND HOROLOGY, we offer a curated selection of watches ranging from vintage to modern, including both brand-new and pre-owned timepieces. We’re committed to quality, accuracy, and integrity. Our listings feature:

Professional, unedited photography and clear, transparent descriptions. Every watch is thoroughly inspected and securely packaged to ensure a confident, seamless buying experience.

We also warmly invite you to visit our physical shop and explore the collection in person.

Contact Us

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