Longines UltraChron Ref.8309 Cal.6651 34.5mm 1974

Much popularised with its latest revival would be this wonderful example of the Longines Ultrachron Ref. 8309, produced in the early 1970s and celebrated for its high-frequency movement and robust construction. Housed in a well-proportioned 34.5mm stainless steel case, this piece offers excellent wrist presence while maintaining elegant vintage proportions. The crisp silver sunburst dial is complemented by applied indices, black-insert hands, and a practical date display. Combined with the original crown and beautifully preserved case, this is a highly collectible watch that perfectly embodies Longines’ golden era of innovation.

In addition, this timepiece comes freshly serviced with all parts laid out by our professional watchmaker for all to see in the images above. Little to no other dealers do this and it’s a testament to full transparency here at Montre D’or. With the Cal.431 inside running excellently as shown in the timegrapher reading above, just like it was when it left the factory over half a century ago.

DIAL:

• Original silver sunburst crosshair dial in excellent condition

• Baton hands with black inserts, no tritium lume

• Applied hour indices with black inserts

• Applied Longines logo and original wording

• Date window at 3 o’clock with quickset feature

• Domed acrylic crystal, unsigned at center

CASE:

• Classic tonneau-style stainless steel case

• 34.5mm (excluding crown) / 41mm lug-to-lug / 9mm thickness

• Professionally polished with all sharp edges intact

• Original Longines-signed crown at 3 o’clock

CASEBACK:

• Screwdown caseback

• Professionally polished to perfect vintage condition

• Comes with plastic protective sticker as shown

MOVEMENT:

• Longines Cal. 431 – Automatic high-beat movement

• 17 jewels / ~42-hour power reserve / 36,000 vph

• Quickset date function (advance by repeated crown pulls)

• Movement freshly serviced and in excellent condition

• Last serviced: February 2026

• Accuracy:~0s/day

STRAP:

• Handmade black crocodile leather strap, 18mm lug width

• Aftermarket Longines signed stainless steel buckle

AFTERCARE PACKAGE:

• Comes with a black wooden box + silica gel

• Complimentary PolyWatch crystal polishing kit (for acrylic crystal)

• 6-month warranty (covers non-user damage only)

• Guarantee Certificate with full service details included

• Access to our exclusive post-warranty repair services

• 7-day return policy for peace of mind

SPECIFICS:

Maker: Longines

Model: Ultrachron

Year: 1974

Case Material: Stainless Steel

Reference: 8309

Movement Serial: 51436367

Caliber: 431

Diameter: 34.5mm

Lug to lug: 41mm

Lug width: 18mm

Thickness: 9mm

Lume: None

Strap: Handmade crocodile leather

Box and papers: None

Accuracy: ~0s/day

Movement type: Automatic High-Beat

Crystal: Acrylic

Crown: Original signed crown

Last service: February 2026

Free express tracked shipping with signature upon delivery. Delivery within Singapore in 1-2 working days. International shipping may take 2–12 working days depending on destination. Do note respective custom duties might apply which includes the recent US tariffs and are the buyer's responsibility.

Do note that for US bound shipments the PolyWatch polishing kit will not be included in order to mitigate customs delay due to new customs requirements

Countries that we do not ship to: Algeria, Nepal, Pakistan, Russia, Vietnam, Iran

This is a vintage timepiece and water resistance is not guaranteed. Please avoid contact with water or moisture. Store the watch with dry tissue or silica gel to preserve its condition. We are not liable for water damage post-purchase.