Longines UltraChron Chronometer Ref.8351 Cal.6651 34.5mm 1974

A sharp, high-beat vintage dress piece from Longines’ golden era of precision, this UltraChron Chronometer Ref.8351 pairs understated elegance with serious mechanical credibility. Housed in a clean stainless steel case and powered by the Cal.6651, it features its original signed crown and a striking set of hands with black inserts. Making it the kind of refined daily wear vintage that still feels quietly special on the wrist.

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.6651 inside running excellently as shown in the timegrapher reading above, just like it was when it left the factory nearly half a century ago.

DIAL:

• Original silver dial in honest vintage condition

• Gorgeous hands with tritium lume inserts

• Applied hour indices with matching lume plots

• Applied Longines logo and original wording

• Date window at 3 o’clock with semi-quickset feature (varies by configuration)

• Original domed acrylic crystal

CASE:

• Classic square stainless steel case with sharp vintage lines

• 34.5mm (excluding crown)/ 38mm Lug-to-lug / 10mm thickness

• Professionally polished with all sharp edges intact

• Original Longines-signed crown at 3 o’clock

CASEBACK:

• Screwdown caseback with iconic UltreChron emblem

• Professionally polished to perfect vintage condition

• Comes with plastic protective sticker as shown

MOVEMENT:

• Longines Cal. 6651 – Automatic

• 25 jewels / 40-hour power reserve / 28,800 vph

• Semi-quickset date function (Date set by turning crown in 3rd position between 11.45pm-12.10am)

• Movement freshly serviced and in excellent condition (Do note manual winding can be stiffer than other watches as it’s the norm for this caliber)

• Last serviced: January 2026

• Accuracy: ~0s/day

STRAP:

• Handmade black crocodile leather strap, 18mm lug width

• Aftermarket stainless steel Longines signed 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: Ultra-Chron Chronometer

Year: 1974

Case Material: Stainless Steel

Reference: 8351

Movement Serial: 51402759

Caliber: 6651

Diameter: 34mm

Lug to lug: 40mm

Lug width: 18mm

Thickness: 10mm

Lume: Tritium

Strap: Handmade Crocodile Leather

Box and papers: No

Accuracy: ~0s/day

Movement type: Automatic

Crystal: Original Domed Acrylic

Crown: Original Longines-signed crown

Last service: January 2026

Free express tracked shipping with signature upon delivery. Delivery within Singapore in 1-2 working days. International shipping may take 4–12 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.