If you’ve shopped for a rubber watch strap recently, you’ve probably run into two terms that get used almost interchangeably: silicone and FKM. Both are described as “rubber,” both are waterproof, and both look broadly similar in a product photo. So it would be easy to assume the choice comes down to colour and price.
It doesn’t. Silicone and FKM are genuinely different materials with different strengths, and the gap between them shows up exactly where it matters — on your wrist, in the water, and after a year of daily wear. Choosing the right one is the difference between a strap that feels perfect for your lifestyle and one that quietly disappoints.
This guide breaks down what each material actually is, how they compare across the things you care about, and which one makes the most sense for you. By the end you’ll be able to read a product page and know instantly whether you’re looking at the right strap. If you’d rather just browse, you’ll find both types in our rubber straps collection.
What Is a Silicone Rubber Strap?
Silicone is the material most people picture when they hear “rubber strap.” It’s a soft, synthetic elastomer that has been the default for sports and dive straps for decades, and for good reason.
Silicone is prized for its flexibility and immediate comfort. It’s soft against the skin, bends easily around the wrist, and feels good the moment you put it on — there’s no break-in period. It handles a wide temperature range, resists UV without cracking, and is completely waterproof, which makes it a dependable everyday choice.
It’s also more affordable to produce, which keeps the price accessible. For a huge number of wearers, a quality silicone strap is all the strap they’ll ever need.
The trade-offs are subtle but real. Silicone’s soft, slightly tacky surface tends to attract dust, lint, and hair, so darker straps can look like they need a wipe more often. That same softness makes it a little more prone to nicks and small tears over years of hard use, and its surface texture, while comfortable, doesn’t hold fine, crisp detailing quite as sharply as a firmer material can.;
What Is an FKM Rubber Strap?
FKM stands for fluoroelastomer — a high-performance synthetic rubber you may also see referred to by the trade name Viton. It’s the material used in the premium aftermarket straps that aim to match or beat the feel of an original luxury band, and it sits a clear step up the quality ladder from standard silicone.
The defining quality of FKM is durability. It’s denser and more resilient than silicone, with superb resistance to abrasion, ageing, and general wear. It shrugs off chemicals that would trouble other rubbers — chlorine, saltwater, sunscreen, oils, and solvents — which is why it’s a favourite for serious dive and water use. Our FKM rubber band for the Blancpain Fifty Fathoms is a good example of the material doing exactly the job it was made for.
FKM also holds detail beautifully. Its firmer surface takes crisp textures, ribbing, and embossed patterns and keeps them looking sharp, giving the strap a more refined, high-end appearance. And because the surface is less tacky than silicone, it repels dust and lint far better, so it stays looking clean with less effort.
The trade-offs here are price and feel. FKM costs more, both as a raw material and to manufacture well. And because it’s denser and less stretchy than silicone, some wearers find it feels slightly firmer at first, though quality FKM straps are still very comfortable and mould to the wrist with wear.
FKM vs. Silicone: The Head-to-Head
With the basics covered, here’s how the two materials stack up across the categories that actually influence day-to-day satisfaction.
Durability and Longevity
This is FKM’s clearest win. Its density and resilience mean it resists nicks, abrasion, and the slow degradation that eventually affects softer rubber. A well-made FKM strap will typically outlast a silicone one, holding its finish and structure for longer under the same conditions. Silicone remains perfectly durable for everyday wear — it just tends to show the years a little sooner.
Comfort and Feel
Silicone has the edge in pure out-of-the-box softness. It’s supple and pillowy from the first wear, which some people simply prefer. FKM feels a touch firmer initially but is by no means uncomfortable, and many wearers actually prefer its more substantial, “quality” feel once it has settled in. This one comes down to personal taste.
Water and Chemical Resistance
Both are fully waterproof, so for swimming and everyday splashes either is fine. But if you dive, spend real time in saltwater, or expose your strap to chlorine, sunscreen, and oils, FKM’s superior chemical resistance makes it the safer long-term choice.
Appearance and Cleanliness
FKM’s less tacky surface resists dust, lint, and fingerprints, and its firmness holds textured designs crisply — both of which give it a more premium look that’s easier to keep clean. Silicone looks great too, but darker colours in particular will ask for a wipe more often.
Price
Silicone is the more budget-friendly option and delivers excellent value. FKM commands a higher price that reflects its material cost and performance. Think of it as paying more up front for a strap that lasts longer and looks sharper.
Maintenance
Both are wonderfully low-maintenance — a rinse with mild soap and water keeps either looking fresh. FKM’s dust resistance simply means you’ll reach for that cloth a little less often.
Which Rubber Strap Should You Choose?
There’s no universally “better” material — only the right one for how you live.
Choose silicone if you want maximum softness from the first wear, you’re after excellent value, or you simply want a comfortable, waterproof everyday strap that does the job without fuss. For casual wear, the gym, and general daily use, silicone is a genuinely great choice.
Choose FKM if you’re a diver or spend serious time in and around water, you want the longest-lasting strap with the most premium look and feel, or you’re dressing a high-end watch and want a band that matches its quality. FKM is the enthusiast’s pick and the closest aftermarket match to a luxury original.
Whichever way you lean, getting the fit right matters just as much as the material. Before you order, take a moment to confirm your lug width using our guide on how to measure your watch strap — the best strap in the world won’t feel right in the wrong size.
The Bottom Line
Silicone and FKM are both excellent rubber straps that happen to excel at different things. Silicone offers softness, value, and easy everyday comfort. FKM offers durability, chemical resistance, and a premium finish that stands up to years of hard use. Now that you know how to tell them apart, you can choose with confidence rather than guessing from a product photo.
Ready to find yours? Explore both materials in our full rubber straps collection and match the strap to the life you actually lead.
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