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- ISOfrane 1968 Rubber Watch Strap - Black
ISOfrane 1968 Rubber Watch Strap - Black
Original ISOfrane dive strap design, reintroduced by Synchron.
The ISOfrane dive strap traces its roots to the early era of professional dive watches. First introduced in the 1960s, its distinctive vented design and substantial rubber construction quickly made it a favorite among serious dive watch manufacturers.
Reintroduced by Synchron in 2010, today’s ISOfrane straps preserve the original tool-watch character while benefiting from modern materials and production.
Material & feel
ISOfrane straps are made from a proprietary isoprene rubber compound that offers greater density and resilience than typical rubber. The material is 100% silicone-free, hypoallergenic, non-toxic, and waterproof, making it well suited for prolonged contact with skin and regular water exposure. The rubber is lightly vanilla-scented and does not attract lint or dust the way silicone straps often do.
The strap features a ribbed underside to reduce adhesion against the skin, along with large ventilation slots that promote airflow and water drainage. Hardware is ISOfrane’s Retrosicuro buckle, available in brushed stainless steel or black DLC (diamond-like carbon) finish.
Learn more in our Rubber Watch Strap Guide.
Sizing & specs Length, taper, spring bars, buckle finish and more
Taper:
- 20mm lug / 20mm buckle
- 22mm lug / 22mm buckle
Popular watch pairings
20mm strap width fits:
- Glycine Combat Sub 39
- Omega Seamaster Diver 300M
- Omega Speedmaster Professional
- Rolex Submariner
- Tudor Black Bay Fifty-Eight
22mm strap width fits:
- Orient Kamasu
- Orient Ray II
- Tudor Black Bay
Wear & care
Swim ready, suitable for swimming and regular water exposure.
Clean with lukewarm water and mild soap as needed. Rinse thoroughly and allow to air dry fully. Avoid solvents, abrasives and petroleum-based cleaners.
About the brand
ISOfrane emerged during the early years of modern dive watches, developing rubber straps intended for extended use in demanding underwater conditions.
Today’s ISOfrane straps remain closely aligned with the original late-1960s design, emphasizing functional geometry and dive-focused utility rather than stylistic trends. Revived by Synchron, modern production preserves the character of the original while improving consistency and durability.
Shipping
Orders placed by 2:00pm PST on business days typically ship the same day.
Tracking is included with every order and emailed at shipment.
United States
- USPS Ground Advantage: free on orders over $59, or $6.95 on orders up to $59. 3 to 6 business days.
- USPS Priority Mail: $11.95. 2 to 4 business days.
- USPS Priority Mail Express: $28.95. 1 to 3 business days.
International
- USPS First Class International: $18.95. 10 to 21 business days.
For complete shipping details, see our Shipping Policy.
Returns & exchanges
Unused items may be returned or exchanged within 60 days of purchase. Please contact us before sending an exchange.
For full return details and instructions, see our Returns Policy.
- 5 stars: 13 (93%)
- 4 stars: 1 (7%)
- 3 stars: 0 (0%)
- 2 stars: 0 (0%)
- 1 star: 0 (0%)
Got this strap for my Tissot Seastar to add a professional touch. Fits perfectly and I love the vent holes they give some 80’s vibes. Strap is thick but still supple enough to fit comfortably on the wrist. I did not notice any vanilla scent but that’s fine.
I upgraded the 22mm watch band on my Garmin Fenix 8 with the Isofrane band. I like the appearance, rubber softness, buckle, and overall quality of the band. Initially, the band was not as comfortable as I liked and the strap keepers were difficult to put in place. However, after several days of use the band has become very comfortable and the keepers easier to use. I am very happy with the overall quality, appearance, and comfort! Highly recommended.
I waffled back and forth before finally deciding to pull the trigger on this strap.
I highly recommend ISOfrane and I highly recommend Holben’s!
When you’re done messin’ around buying strap after strap looking for the right one…come back here and just get the ISOfrane dive strap.
It’s thick, soft, supple, grippy and crazy comfortable.
I bought this new Seiko Yellow Tina, wanted a yellow Isofrane strap to go with it. I turned to Holbens because of price, they were able to post to Australia.
It’s a very comfortable strap, the yellow strap smells like vanilla, where as my black Isofrane doesn’t!
The strap arrived before my watch did, fitting it was easy. It’s only a weekend watch for me.
The keepers with the Isofrane are very snug, & I must position them in place before putting it on.
In all, I’m very happy with the strap, & am looking at another purchase in future with Holbens.
Immediately fell in love with this band the second it was installed, It doesn’t even feel like I’m wearing a watch with this band
If you've never handled an ISOfrane rubber strap before, you are missing out. This strap is absolutely top of the line in every way. Fantastic quality and comfort. The best hardware in the game, too. I picked up a black with black PVD buckle for my Seiko "Darth Tuna". Perfect match... better than OEM strap!
I was looking for a rubber strap for my Sinn U1, which I’d been wearing on the factory bracelet. I have the Sinn rubber strap with large deployant on my U2 and EZM2B and wanted something that was comfortable and had a lower profile than the OEM rubber strap. The Isofane fit that bill, plus it looks great.
It looks good and makes a big lunker dive watch comfortable to wear. The best part is the holes are spaced closely together so you get fine adjustment.
Picked up this Isofrane strap to use on various divers in my collection. The NATO green shade is perfect and will go with just about any watch. Super high quality and beautiful to behold. Fantastic vanilla scent. Can't say enough good things about this strap!
I bought this strap to go with my Synchron Military Black, and it goes very well. Nice look. It is, however, rather difficult to put on the wrist. The strap does not slide on itself that easily, making it hard to get it through the keepers. This is the reason for the 4 stars.
The ISOFrane is about as nice of a strap as you can get for a dive watch. It's comfortable, the keepers are well designed, and it's breathable on the wrist. Highly reccomended.
Every reviewer I checked out seemed to feel that this strap was top notch. I fully agree.
Amazing strap for comfort on hot summer days. Made of thick rubber. I don’t really notice the “vanilla smell” some people are talking about. Only thing I’d change would be the length of the strap. It’s almost too long even on my 7.5” wrist. Oh and the price is pretty steep but you get what you pay for. Like usual, the strap shipped very fast.
I was looking for a new strap to replace the one that came with my Citizen Promaster Dive watch and cannot be any happier with the Isofrane in anthracite that I chose. It is a high quality rubber strap that perfectly complements the watch. A very rugged look that matches the tool watch aesthetics of the watch, while also being high quality. I’m sure this strap, like the watch, will serve me well for many years. Purchase from Holben’s was fast and easy. Despite being shipped across the country, I received the strap quickly. First time customer, but it won’t be my last purchase!