Best Watch Straps for the Aquastar Benthos Professional

The Aquastar Benthos Professional is the result of years of consultation with professional and commercial divers. Not recreational divers who wear their watches to the pool — working divers who depend on their instruments under pressure and in conditions that would compromise most watches sold to enthusiasts. Rick Marei, who heads Aquastar, has described the development process directly: feedback from the people who use dive watches professionally informed every specification decision. The Benthos Professional is the outcome.

The name carries historical weight. The original Benthos 500 from 1970 was the first non-monobloc cased dive watch designed to operate at 500 metres depth. It represented a genuine engineering advance — a case construction that separated the caseback from the case body, enabling a more secure seal at extreme pressure. The 500 metre rating was not marketing. It was a specification requirement for commercial diving operations in the North Sea and elsewhere.

The modern Benthos Professional takes the dimensions of the original — 42mm diameter, 47mm lug-to-lug — and slims the profile from the original's thickness to 13.7-13.9mm. The Two Broke Watch Snobs reviewer described the reduction immediately: "The first thing I noticed when I put the Benthos Professional on the wrist wasn't the DLC or the bezel. It was the profile." A slimmer Benthos is a more wearable Benthos — the watch moves from occasional impressive piece to genuine daily companion.

The Sellita SW200-1 in Elaboré grade, 904L stainless steel case, 120-click ceramic bezel, triple-coated AR sapphire crystal, helium release valve at 4:00, and crown at 2:00 — the asymmetric crown position is the Aquastar signature, inherited from the original Benthos and retained across every modern reissue. The ISOfrane rubber strap is itself a reissue of the 1969 ISOfrane original — one of the most respected professional dive rubber straps ever produced.

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Aquastar Benthos Professional Strap Size — Two Variants, Two Lug Widths

The Aquastar Benthos Professional comes in two distinct variants with different lug widths. Always identify your specific reference before ordering.

Current Benthos Professional (904L stainless steel and DLC, 2025) — 20mm watch straps — confirmed directly by Aquastar's own current product page ("Lug Width: 20mm") and Fratello hands-on review ("solid 20mm end links" on the bezel-of-rice bracelet). 42mm 904L case, 13.7-13.9mm thick, 47mm lug-to-lug. Ships with ISOfrane VS 1969 rubber strap.

Benthos Professional Founder's Edition / Benthos 500 II (316L steel, limited 300 pieces) — 22mm watch straps — confirmed by Aquastar's own product page ("22mm lugs") and ISOfrane strap specification ("22mm ISOfrane Rubber"). 42mm 316L case, 15.4mm thick, 47mm lug-to-lug. Ships with 22mm ISOfrane rubber.

Quick reference:

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The ISOfrane — What Aquastar Ships With

Aquastar ships the Benthos Professional with a genuine ISOfrane rubber strap — a re-edition of the 1969 ISOfrane original. The ISOfrane is one of the most historically significant professional dive rubber straps ever produced — designed for professional use with a distinctive tapered shape and ladder construction. Aquastar's choice of ISOfrane as the factory strap is a deliberate heritage reference: the original Benthos 500 was worn on ISOfrane rubber by the divers it was designed for.

The ISOfrane is an excellent strap. The aftermarket opportunity is for those who want a different material character — tropical FKM for vintage texture, marine Nationale elastic for comfort, leather for everyday dress-sport use.

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Best Rubber Straps for the Aquastar Benthos Professional (20mm)

Tropical style FKM in black at 20mm watch straps — the most celebrated Benthos Professional rubber combination. The vintage basket-weave and honeycomb patterns reference the same 1970s professional dive watch culture the Benthos was born in. The original Benthos 500 was worn on vintage Tropic and ISOfrane rubber — black tropical FKM continues this heritage in a premium FKM construction.

Brown tropical FKM at 20mm watch straps — for the most warm vintage character. Brown tropical rubber references the aged, patinated rubber of original 1970s professional dive watch straps.

Classic FKM rubber in black at 20mm watch straps — the most practical everyday active upgrade.

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Best Rubber Straps for the Benthos Professional Founder's Edition (22mm)

Tropical style FKM in black at 22mm watch straps — same vintage heritage logic at 22mm.

Classic FKM rubber in black at 22mm watch straps — practical active upgrade from the factory ISOfrane.

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Best Nylon Straps for the Aquastar Benthos Professional

Single-pass nylon — Original at 20mm watch straps or 22mm watch straps with the CNS solid buckle depending on variant. Most appropriate Benthos Professional colourways:

• Black — the most operationally unified combination
• Olive / khaki — for the most vintage professional dive and expedition character
• Navy — for a maritime professional diver combination
• Admiralty Grey — the most composed operational colourway

Marine Nationale elastic at 20mm watch straps or 22mm watch straps — the most comfortable Benthos Professional daily wear option. The French Navy combat swimming heritage connects directly to the Benthos's own professional diving brief. Black or navy.

RAF single-pass nylon at 20mm watch straps or 22mm watch straps — for the most specifically European military dive heritage combination.

Canvas at 20mm watch straps or 22mm watch straps in olive — for a vintage professional diver character.

Paratrooper elastic at 20mm watch straps or 22mm watch straps — the most comfortable daily option.

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Best Leather Straps for the Aquastar Benthos Professional

Leather transforms the professional diver into a compelling everyday sport-dress piece. The Benthos Professional's slimmer 13.7-13.9mm profile makes it more leather-compatible than the original 500 — a specific design improvement that enhances everyday wearability.

Leather watch straps in dark brown at 20mm watch straps — the most characterful Benthos Professional leather combination. Warm brown against the brushed 904L case creates a warm-cool contrast that reveals the watch's character as a genuine everyday sport-dress piece. Full-grain calfskin develops patina that the factory rubber cannot replicate.

Leather watch straps in black at 20mm watch straps — the most formally correct combination. Particularly appropriate for the DLC black variant — black leather on black DLC creates a unified stealth combination.

Leather watch straps in tan suede at 20mm watch straps — the most relaxed everyday combination.

Leather watch straps in dark brown suede at 20mm watch straps — for smart-casual contexts.

For the Founder's Edition at 22mm watch straps — same leather recommendations apply at the larger lug width.

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The DLC Variant — Specific Strap Logic

The black DLC-coated Benthos Professional has a uniformly dark case. Black rubber creates a unified stealth combination. Tropical FKM adds vintage texture. Olive or khaki nylon creates the most striking contrast against the dark case. Brown leather creates warm-cool contrast between warm leather and cool black case.

All at 20mm watch straps.

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The Aquastar Heritage Cluster

Aquastar Benthos Professional (current 904L/DLC) — 20mm watch straps. The slimmed professional diver.

Aquastar Benthos Professional Founder's Edition — 22mm watch straps. The limited 316L chronograph variant.

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Recommended Combinations

Most historically coherent — black tropical FKM at 20mm watch straps — vintage rubber heritage on the professional diver.

Most warm vintage — brown tropical FKM at 20mm watch straps.

DLC most coherent — black leather or black FKM rubber at 20mm watch straps.

Most characterful leather — leather watch straps in dark brown at 20mm watch straps.

Most comfortable daily — Marine Nationale elastic at 20mm watch straps.

Most operational — black single-pass nylon at 20mm watch straps.

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Frequently Asked Questions

What size strap does the Aquastar Benthos Professional take? It depends on the variant. The current 904L stainless steel and DLC Benthos Professional uses 20mm watch straps — confirmed by Aquastar's own product page and Fratello hands-on review. The Founder's Edition / Benthos 500 II uses 22mm watch straps — confirmed by Aquastar's own product page. Always confirm your specific reference before ordering.

What is the best strap for the Aquastar Benthos Professional? Black tropical style FKM at 20mm watch straps for the most historically coherent combination — the vintage basket-weave rubber references the original Benthos 500's own ISOfrane and Tropic rubber culture. Dark brown leather for the most celebrated everyday sport-dress transformation.

What is the ISOfrane strap? The ISOfrane is a professional dive rubber strap originally designed in 1969 — one of the most respected professional dive straps ever produced. Aquastar ships the Benthos Professional with a genuine ISOfrane VS 1969 re-edition strap, maintaining direct continuity with the original 1970 Benthos 500's factory strap. The ISOfrane has a distinctive tapered shape and ladder construction that differs from standard flat-end rubber straps.

What is the difference between the Benthos Professional and the Benthos H1? The Benthos H1 retains the exact original 1970 Benthos 500 dimensions including its original thickness. The Benthos Professional takes the same 42mm diameter and 47mm lug-to-lug but significantly reduces the thickness to 13.7-13.9mm for improved everyday wearability. The Two Broke Watch Snobs reviewer described this profile reduction as the watch's most immediately noticeable improvement.

What movement does the Aquastar Benthos Professional use? The Sellita SW200-1 in Elaboré grade — a Swiss-made automatic movement adjusted in multiple positions with 38 hours of power reserve. The Elaboré grade indicates a higher quality finish and regulation than the standard grade, appropriate for a watch at this price point.

All CNS straps for the Aquastar Benthos Professional are available at 20mm watch straps (current 904L/DLC) and 22mm watch straps (Founder's Edition). Standard delivery worldwide. 30-day returns.