2026-05-11
Best Watch Straps for the Marathon GSAR
The Marathon GSAR is not a watch that made its reputation through marketing. It made it through government procurement. The GSAR — Government Search and Rescue Automatic — is developed to Canadian and US government requirements for use by search and rescue professionals operating in some of the most demanding environments on earth: arctic conditions, open water rescue operations, mountain rescue, and military special operations. The watch is produced under active US government contract and has been issued to members of the Canadian Armed Forces, the US military, and various armed special operations units.
Marathon Watch Company is based in La Chaux-de-Fonds, Switzerland — the same town that houses Longines, TAG Heuer, and IWC Schaffhausen — and has been producing military watches since 1904. The GSAR's movement is regulated and assembled in La Chaux-de-Fonds, and the watch bears genuine Swiss Made certification alongside its MIL-SPEC markings.
The GSAR's specific technical credentials: ISO 6425 certified dive watch, 300m water resistance, unidirectional rotating bezel, screw-down crown with angular crown guards, tritium gas tube lume — Maraglo™ technology that glows continuously for 25 years without charging — and a 41mm brushed stainless steel case with drilled lug holes. The tritium tubes on the GSAR's dial and hands are not merely a design choice. They are the reason military procurement chose this watch: a rescue swimmer cannot charge lume before entering dark water at 0300.
Marathon GSAR Strap Size
The Marathon GSAR uses 20mm lugs — confirmed by Marathon's own official specifications, multiple owner measurements, and the Eastern Watch Collection review which measured the lug width directly.
GSAR WW194006 (stainless steel, black dial) — 20mm. 41mm case, 14mm thick, 48mm lug-to-lug. Drilled lugs.
GSAR Anthracite (IP-coated black case) — 20mm. Same dimensions.
GSAR Arctic Edition (white dial) — 20mm. Same dimensions.
GSAR with Government markings — 20mm. Same dimensions — the "US Government" dial text does not affect case dimensions.
Marathon's own strap range for the GSAR is listed as 20mm including their Two-Piece Rubber Dive Strap and Nylon DEFSTAN Strap — confirming 20mm as the factory specification.
Important: Delugs incorrectly lists the GSAR at 18mm — this is wrong. An 18mm strap will leave a visible gap on both sides of the 20mm lugs. Order 20mm.
The GSAR's Character — MIL-SPEC Without Compromise
The GSAR is a working instrument. Its design is entirely determined by the Canadian and US government MIL-SPEC requirements it was built to meet — not by aesthetic trends, not by homage to vintage references, and not by collector preferences. Every feature exists for a reason. The oversized crown guards protect the crown during physical operations. The drilled lugs allow field strap replacement without tools. The angular case prevents the watch rolling on a flat surface. The 300m water resistance covers professional combat diving.
This character creates a strap logic: operational straps first, leather for off-duty contexts, nothing that contradicts the working tool character. Marathon ships the GSAR with a three-piece rubber strap kit and offers their DEFSTAN nylon as a factory alternative. Both are correct choices. Both reference the watch's actual operational heritage rather than a borrowed aesthetic.
Best Rubber Straps for the Marathon GSAR
Classic FKM rubber in black at 20mm — the most operationally correct and most factory-validated GSAR combination. Marathon ships the GSAR with vulcanised rubber as standard. Black FKM is the most direct upgrade from the factory rubber — more UV-resistant, more durable over time, and with better colour retention than the factory vulcanised rubber.
Tropical style FKM in black at 20mm — the most collector-appropriate rubber choice. The vintage basket-weave texture references the era of professional military diving equipment from which the GSAR's design lineage descends. For a watch used by the Canadian SAR community since the early 1990s, vintage-textured rubber creates a period-coherent character.
Brown tropical FKM at 20mm — for the most warm and most specifically vintage combination. Effective on the standard black dial GSAR.
Grey FKM rubber at 20mm — for the Anthracite IP-coated GSAR. Grey rubber against the dark anthracite case creates a unified, cool-toned operational palette.
Best Nylon Straps for the Marathon GSAR
Nylon is the most authentic strap choice for the GSAR. Marathon offers their own DEFSTAN nylon strap as a factory option — the DefStan 66-15 specification nylon that CNS builds its single-pass range around. Both are built to the same British and military defence standards specification.
Single-pass nylon — Original at 20mm with the CNS solid buckle — the direct equivalent of Marathon's own DEFSTAN factory nylon in CNS's construction. Most appropriate GSAR colourways:
- Black — the most operationally correct and most minimal. Black single-pass on the GSAR creates the most purposeful operational combination.
- Olive / khaki — for the most specifically military SAR-adjacent aesthetic. Canadian and US SAR operators work in environments where olive and earth tones are operationally appropriate.
- Admiralty Grey — the MOD specification colourway, matching the DefStan heritage of both Marathon and CNS nylon directly.
- Black and grey — the most understated collector combination.
RAF single-pass nylon at 20mm — the RAF 6B/2617 specification shares the same British defence procurement world as the DEFSTAN nylon Marathon offers. Both exist within the same armed military equipment standard framework.
Marine Nationale elastic at 20mm — the most comfortable GSAR daily wear option. The French Navy combat swimmer heritage of the Marine Nationale strap places it directly in the professional military diving world the GSAR was designed for. Navy or black.
Canvas at 20mm in olive or black — for the most specifically military equipment-adjacent fabric combination.
Paratrooper elastic at 20mm — the most comfortable daily option.
Best Leather Straps for the Marathon GSAR
Marathon ships the GSAR on rubber and offers nylon as an alternative — leather is not a factory option. However the 20mm drilled lugs accept leather straps directly, and leather creates a specific transformation: the military contract dive watch becomes a characterful everyday sport piece.
The GSAR's 14mm case thickness means it suits moderately padded rather than very slim leather.
Brown vintage two-stitch calfskin at 20mm — the most characterful GSAR leather combination. The warm brown creates a temperature contrast against the brushed steel case and the GSAR's cool operational character. The two-stitch construction references the field equipment world in which the GSAR operates — worn leather from professional operations rather than polished dress leather.
Dark brown padded calfskin at 20mm — the most proportionally appropriate everyday leather. The padded construction suits the GSAR's 14mm case thickness.
Classic black calfskin at 20mm — the most formal combination.
Tan suede at 20mm — the most relaxed leather option. Matte suede suits the fully brushed case's own anti-reflective surface philosophy.
The Dial Variants — Specific Notes
Government markings dial (WW194006-GO) — the "U.S. Government" text and military serial number markings on the dial are a statement of actual procurement heritage. For this variant specifically, operational nylon and black rubber honour the government contract character. Brown leather creates the most interesting off-duty contrast.
Standard dial (no government markings) — more versatile across strap materials. The clean black dial with tritium tube indices suits both operational and smart-casual combinations.
Arctic Edition (white dial) — the white dial creates a different palette from the standard black. Grey FKM rubber for a cool tonal combination; olive nylon for operational contrast; brown vintage two-stitch leather for the most characterful warm-cool contrast.
Anthracite IP-coated case — the dark, hard-coated case suits dark straps that continue the monochromatic palette: black FKM rubber, black single-pass nylon, grey FKM.
Recommended Combinations
Most operationally correct — black FKM rubber at 20mm — following Marathon's own factory specification.
Most factory-authentic nylon — black single-pass nylon at 20mm — the DEFSTAN specification CNS nylon matching Marathon's own factory nylon offering.
Most SAR-coherent — olive single-pass nylon at 20mm — field operations palette.
Most collector-appropriate active — black tropical FKM at 20mm.
Most characterful leather — brown vintage two-stitch calfskin at 20mm — warm leather on a cold-weather operations instrument.
Arctic Edition — grey FKM for cool tonal coherence; brown vintage two-stitch for warm contrast.
Anthracite — black FKM or grey FKM for unified dark palette.
Frequently Asked Questions
What size strap does the Marathon GSAR take? 20mm — confirmed by Marathon's own official specifications and multiple independent owner measurements. Some sources including Delugs incorrectly list 18mm — this is wrong. An 18mm strap will leave a visible gap on both sides. Marathon's own DEFSTAN nylon and rubber strap listings confirm 20mm.
What is the best rubber strap for the Marathon GSAR? Black FKM rubber at 20mm — the most operationally correct combination and the direct upgrade from Marathon's own factory vulcanised rubber. Black tropical FKM for the most characterful collector combination.
What is the best nylon strap for the Marathon GSAR? Black single-pass nylon at 20mm — the CNS DEFSTAN specification nylon matches the construction standard of Marathon's own factory nylon offering. Olive nylon for the most specifically SAR-operational colour combination.
What does "GSAR" stand for? Government Search and Rescue Automatic. The name refers directly to the watch's procurement context — it was developed to Canadian government requirements for use by professional search and rescue operators and has been issued under active US and Canadian military contracts.
What is tritium lume and why does the GSAR use it? Tritium is a radioactive isotope of hydrogen that produces light continuously through radioluminescence — no charging required. The GSAR uses tritium gas tubes (Maraglo™) that glow continuously for 25 years. This is operationally critical for search and rescue operations conducted in complete darkness, underwater, or in conditions where the operator cannot charge standard Super-LumiNova. The tritium tubes mean the GSAR's dial is readable 24 hours a day, 365 days a year, without any preparation.
Does the Marathon GSAR have drilled lugs? Yes — all GSAR references have drilled through-lug holes, allowing spring bar replacement with a standard 1mm fork spring bar tool from the outside of the lug. Marathon designed the lugs this way to meet the MIL-PRF-46374G standard requirement for field-maintainable watches.
All CNS straps for the Marathon GSAR are available at 20mm. Standard delivery worldwide. 30-day returns.