Longines Ultra-Chron Jumbo Ref.8301-7 Cal.431 37.0mm 1973

A superb example of a high-beat jumbo from Longines’s precision era, this 37.0mm jumbo sized Ultra-Chron features a distinctive sunburst dial with an elegant central crosshair, faceted steel pencil hands, and matching faceted hour indices. The original domed acrylic crystal remains clear and intact, enhancing its vintage charm while preserving the dial’s pristine presentation.

Encased in full stainless steel with a commanding 37.0 mm diameter and professionally polished to retain sharp, defined edges, the watch carries a signed Longines crown and screw-down caseback embossed with the famous Ultra-Chron emblem. Inside beats the legendary Cal.431, a 36,000 bph high-beat automatic movement once touted as “the world’s most accurate watch,” recently serviced and running excellently as shown in the last few images.

DIAL

• Silver sunburst dial with central crosshair

• Baton hands with matching faceted indices

• Applied Longines logo and “Ultra-Chron” text, both crisp and original

• Original Longines domed acrylic crystal

CASE

• Full stainless steel, professionally polished to retain its sharp edges

• 37.0mm (excluding crown) / 42.0mm lug-to-lug / 10.0 mm thickness

• Screw-down caseback featuring the original Ultra-Chron emblem

• Original Longines-signed coin edge crown

MOVEMENT

• Longines Caliber 431 – Automatic high-beat movement

• 25 jewels / 50-hour power reserve / 36,000 bph

• Semi-quickset date (advance by rotating between 10 PM–12 AM)

• Movement serial: 50993326

• Last serviced: April 2026

• Accuracy: ~0s/day

STRAP AND BUCKLE

• Handmade leather strap, colour and design can be changed upon request depending on availability

• Aftermarket Omega stainless steel buckle

AFTERCARE PACKAGE

• Comes with a black presentation box + silica gel

• Free PolyWatch crystal polishing kit (for acrylic crystal only)

• Warranty card included with service history details

• 6-month warranty (non-user damage)

• Exclusive repair service post-warranty

• 7-day return policy for peace of mind

SPECIFICATIONS

Maker: Longines

Model: Ultra-Chron

Reference: 8301-7

Year: 1973

Caliber: Cal.431

Serial Number: 50993326

Movement Type: Automatic High Beat

Case Material: Stainless Steel

Lume: NIL

Diameter: 37.0 mm

Lug-to-Lug: 42.0 mm

Thickness: 10.0 mm

Lug Width: 18.0 mm

Crystal: Original Domed Acrylic

Crown: Original Longines Signed

Strap: Handmade Leather

Clasp: Aftermarket Longines Stainless Steel

Original Box and Papers: NIL

Accuracy: ~0s/day

Last Service: April 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 and will be shipped via FedEx/UPS/Aramex

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: Afghanistan, Belarus, the Central African Republic, Chad, Cuba, the Democratic Republic of the Congo, Eritrea, Iran, Iraq, Lebanon, Libya, North Korea, Oman, Pakistan, Russia, Somalia, South Sudan, Syria, Ukraine and the Crimea, Donetsk, and Luhansk regions of Ukraine.

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.