Case #655 — Longines HydroConquest GMT 41 “Rootbeer” Ref. L3.790.4.66.6

Case #655 — Longines HydroConquest GMT 41 “Rootbeer”
Ref. L3.790.4.66.6

Status: Available
Condition: Very Good Pre-Owned
Scope: Box, Papers, and Cards

Case Notes

The HydroConquest GMT takes one of Longines’ most capable modern sports-watch platforms and adds a true travel complication without compromising its dive-watch credentials.

This “Rootbeer” configuration is especially distinctive. The sunray brown dial and matching brown ceramic bezel shift noticeably with the light, moving from deep chocolate tones indoors to warmer bronze and copper tones in brighter conditions. Against the stainless-steel case and bracelet, the result feels richer and more refined than the more conventional black or blue versions.

At 41 mm, the proportions are versatile and wearable, while the Longines Calibre L844 provides GMT functionality, approximately 72 hours of power reserve, and a silicon balance spring.

This example dates from 2024 and presents in very good pre-owned condition. It includes its box, papers, and cards and is currently sized for approximately a 7¾-inch wrist.

The Evidence

Reference: L3.790.4.66.6
Model: HydroConquest GMT
Year: 2024
Case: Stainless Steel
Case Diameter: 41 mm
Thickness: Approximately 12.9 mm
Lug Width: 21 mm
Dial: Sunray Brown
Crystal: Sapphire with Anti-Reflective Coating
Bezel: Unidirectional Rotating Brown Ceramic
Crown: Screw-Down
Movement: Longines Calibre L844
Movement Type: Automatic GMT
Frequency: 25,200 VPH
Balance Spring: Silicon
Power Reserve: Approximately 72 Hours
Functions: Hours, Minutes, Central Seconds, Date, GMT / Second Time Zone
Water Resistance: 300 meters / 30 bar
Bracelet: Stainless Steel
Clasp: Double-Security Folding Clasp with Micro-Adjustment
Bracelet Fit: Approximately 7¾-inch wrist
Condition: Very Good Pre-Owned
Included: Box, Papers, and Cards

Collector Provenance

The HydroConquest GMT represents a significant evolution of Longines’ established dive-watch line.

Rather than simply adding a fourth hand to the standard HydroConquest, Longines built this generation around the L844 automatic GMT movement while retaining the collection’s 300-meter water resistance, ceramic bezel, screw-down crown, and robust sports-watch construction.

The result is a watch that works equally well as a travel companion and as a serious everyday diver.

Design Provenance

The brown configuration is what gives this reference its character.

The sunray dial adds depth and variation rather than presenting as a flat brown surface, while the matching ceramic bezel reinforces the warm palette. The stainless-steel case and bracelet keep the watch grounded and prevent the overall look from becoming overly dressy.

It is an unusual color combination for a modern dive watch, which helps the “Rootbeer” nickname feel appropriate without making the watch look novelty-driven.

From the Case File

At 41 mm and approximately 12.9 mm thick, the HydroConquest GMT offers substantial capability without becoming oversized.

The L844 movement provides approximately 72 hours of power reserve, making the watch practical for rotation as well as travel. The micro-adjustment clasp improves everyday comfort, while the 300-meter water-resistance rating keeps the watch firmly within true dive-watch territory.

This 2024 example adds very good pre-owned condition, a complete BPC presentation, and bracelet sizing to approximately a 7¾-inch wrist.

BST Verdict

A strong modern Longines with real capability and a less conventional personality.

The brown sunray dial and matching ceramic bezel give this HydroConquest GMT a warmer, more distinctive look, while the 41 mm case, L844 movement, 72-hour reserve, micro-adjustment bracelet, and 300-meter rating provide genuine substance.

A complete 2024 example in very good condition makes Case 655 an especially attractive way into one of Longines’ most versatile modern sports watches.

Every case deserves a closer look.