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- ISOfrane 1968 Rubber Watch Strap - Royal Blue
ISOfrane 1968 Rubber Watch Strap - Royal Blue
- Price
- $139
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.
Original ISOfrane dive strap design, reintroduced by Synchron.
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.
Specs at a glance
Thickness: approx. 5.5mm→3.5mm (measured at lug end, tapering toward buckle)
Sheen: Matte
Buckle: Brushed stainless steel
Buckle width by strap size:
- 20mm → 20mm buckle
- 22mm → 22mm buckle
Spring bars: Standard (free pair included)
Sizing & fit help
Isoprene rubber wears with a dense yet flexible feel that keeps the watch firmly supported on the wrist. Compared to typical rubber straps, it has more body and doesn’t feel soft or floppy when worn. The textured underside helps the strap stay stable rather than feeling slick or sealed against the skin.
The two-piece construction creates a balanced, secure wrap, and a generous hole pattern allows for fine adjustment across a wide range of wrist sizes.
Strap length & fit:
130mm / 75mm (fits wrists approx. 7.0–7.75in)
Measurements exclude the buckle.
Apple Watch: The 22mm width is compatible with Apple Watch when used with our strap adapters.
Care & wear
Water exposure: Waterproof, designed for prolonged water exposure including swimming and diving.
Clean with lukewarm water and mild soap as needed. Rinse thoroughly to remove residue. Avoid solvents, petroleum-based cleaners, or abrasive materials. Dry with a soft cloth and allow the strap to air dry completely before wearing.
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.
