Coros · Water-Resistant Smart Rings & Bands
COROS Smartwatch Bands Nylon Quick Release Waterproof Strap
Waterproof nylon strap; coating composition not disclosed.
This nylon smartwatch band is marketed as waterproof, but Coros doesn't disclose the water-repellent coating chemistry. Waterproof textiles commonly use PFAS.
The better-graded swap
IMIKI
IMIKI Smart Ring
85/100 safety
Same rubric that flunked this product. The swap earned Excellent.
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
Nylon with waterproof treatment, coating unspecified
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
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What COROS Smartwatch Bands Nylon Quick is made of, ingredients and materials
This strap is nylon (polyamide), a synthetic polymer chosen for durability and stretch-recovery in wearables. The critical unknown is the waterproof treatment applied to the nylon; manufacturers typically use either Teflon-family coating-based coatings (which may contain PFAS) or polyurethane-based hydrophobic finishes. Coros does not publicly disclose which chemistry is used on this band, making independent hazard assessment incomplete. Nylon itself is generally considered stable and low-risk when untreated, but the coating composition determines actual safety profile.
What’s concerning
No PFAS disclosure
No public statement from the brand about PFAS in this product.
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
Waterproof / stain-resistant treatment
Water-repellent coating treatments have historically used PFAS.
PFAS
Nylon waterproof treatments often rely on C8 or C6 Teflon-family coating; Coros does not disclose which chemistry is used. No test data or certifications are publicly available to rule out PFAS presence.
Source, ATSDR ↗Coating degradation and microparticle shedding
Repeated flexing and washing of the nylon strap can cause the waterproof coating to crack and shed microscopic particles. If the coating is a synthetic polymer (Teflon-family coating or polyurethane), shedding particles may be inhaled or ingested in small amounts; long-term health impact is unknown for uncharacterized coatings.
Skin sensitization from unknown additives in coating or dyes
Waterproof coatings and fabric dyes may contain plasticizers, catalysts, or residual monomers that can migrate to skin on contact, particularly in warm or moist wrist conditions. No allergic reaction reports specific to Coros bands are documented, but risk is present whenever coating chemistry is proprietary and undisclosed.
What’s reassuring
Formaldehyde / VOCs
Nylon fabric finishing can involve formaldehyde-releasing urea-formaldehyde or melamine-formaldehyde resins for wrinkle resistance or cross-linking. No formaldehyde hazard has been reported for Coros bands specifically, but typical nylon wrist straps carry low baseline risk if dyes and finishes are standard.
Source, ATSDR ↗Azo dyes in colored nylon
If the strap is dyed (most are), restricted azo dyes could theoretically be present; however, nylon bands sold in major markets typically comply with EU and US dye restrictions. No specific recalls or testing failures are on record for Coros colored bands.
The full breakdown
The brand's record and disclosure
Coros has not published any material safety disclosures, testing certifications (e.g., Oeko-Tex, GOTS), or statements about chemical restrictions in their smartwatch band products. The company does not appear to have responded to PFAS scrutiny in their supply chain documentation. No major product recalls or chemical hazard alerts specific to Coros bands are on public record. The silence on coating chemistry is the primary concern; transparency is absent where it is most needed.
How it compares in its category
Most third-party smartwatch bands use similar nylon-plus-waterproof-coating designs. Brands like Apple, Garmin, and Fitbit also do not always disclose coating chemistry, though some aftermarket manufacturers (e.g., Nomad, Barton) offer silicone or woven alternatives that sidestep the waterproof-coating question entirely. Coros bands occupy the middle ground, typical material choice, typical lack of transparency, typical price point. If PFAS-free waterproofing is your priority, silicone or untreated fabric straps are more defensible alternatives.
If you buy it
Avoid prolonged heat exposure (hot water wash, dishwasher, direct sunlight for extended periods) as nylon can degrade and any waterproof coating may break down, potentially releasing trapped chemicals or particles. Hand wash in cool water with mild soap; air dry completely before wearing. Replace the band if the coating develops visible cracks, peeling, or loss of water beading. Since the coating composition is unknown, err on the side of replacing rather than prolonging use if visible wear appears. Keep away from chlorine pools; salt water rinsing is gentler than chlorinated environments.
What we don’t know
- Basis
- Model estimate, 35% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Coros has made none
Formulations change between production runs, so check the current label. How we grade.
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More water-resistant smart rings & bands grades
How we score, every product runs through the same public 0-100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.