When Switzerland's ISOfrane debuted in the early 1960s, it literally changed the shape of dive watch straps. Early rubber straps were plasticky and uncomfortable, and became brittle with use in extreme conditions. ISOfrane's innovative design introduced large slots for ventilation and water drainage, along with a ribbed underside to prevent the strap from sticking to the skin. Taking a lesson from the automotive tire industry, the company used isoprene, a rubber compound that maintained structure and aesthetics through prolonged exposure to the elements. This combination of comfort, flexibility and strength created what grew into a legend in the watch world: when the makers of some of the most renowned dive watches of the 1960s and 1970s needed a rubber strap, they chose ISOfrane.
Reintroduced by Synchron Watches in 2010 and made in Italy using an improved proprietary isoprene-based rubber compound for even more durability and softness, these classic, nonallergenic, nontoxic, 100% silicone-free straps are considered among the best on the market today.