Withings · Water-Resistant Smart Rings & Bands
Compatible for Withings Smartwatch Bands, 18mm, 20mm Quick Release New Soft Silicone Sport Replacement Straps for Women
Low risk. Silicone bands lower concern but no transparency.
Silicone elastomer bands are not associated with PFAS material with no surface treatment disclosed. Brand discloses nothing about PFAS.
We flunk more products than we pass. This one earned its grade. How we grade
Material
Silicone elastomer, no surface treatment disclosed
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
What’s concerning
Category baseline
The starting point for this type of product, before anything specific to this product is counted.
No PFAS disclosure
No public statement from the brand about PFAS in this product.
Silicone degradation and surface oxidation
Extended UV exposure or high heat can cause silicone to become brittle, crack, or release small siloxane oligomers; this is rare during normal wrist wear but accelerates if straps are left in direct sunlight or hot cars.
Bacterial or fungal colonization
Although silicone resists microbial growth better than organic materials, poor hygiene (sweat accumulation, infrequent cleaning) can create localized biofilms; risk is behavioral, not material-inherent.
What’s reassuring
Base material not linked to PFAS
The main material recorded for this product is not one associated with PFAS.
Heavy metals
No public recalls or testing reports document heavy metal contamination in Withings silicone bands. The risk exists in the manufacturing supply chain but is not established for this product or brand.
Source, FDA ↗Allergens from silicone additives
Silicone elastomers typically do not contain known allergens like latex or azo dyes, but contact dermatitis from specific additives or accelerators is rare and not reported for Withings bands.
Plasticizer leaching (if TPU blend present)
Withings marketing specifies silicone, not thermoplastic polyurethane, so phthalate-type plasticizers are not a concern; however, full material composition is not public.
The full breakdown
What it's made of and why it matters
These are silicone elastomer straps, a synthetic rubber polymer that is chemically stable and resistant to degradation during normal wrist-worn use. Silicone does not leach toxic monomers like BPA or phthalates under typical body-temperature conditions, and it resists bacterial colonization better than many alternatives. The absence of disclosed surface treatments or coatings suggests a relatively simple formulation, which lowers the risk of hidden additives, though this also means no third-party verification of purity is publicly available.
The brand's record and disclosure
Withings does not publish material safety data sheets, ingredient lists, or third-party certifications (e.g., FDA silicone classification, EU CE marking details) for these bands on publicly available sources. The brand has not issued statements on PFAS avoidance or manufacturing standards specific to wearables, which represents a disclosure gap rather than evidence of contamination. No recalls targeting Withings silicone bands for chemical hazards have been recorded in public databases as of available information.
How it compares in its category
Silicone sport bands show lower concern for off-gassing of volatile compounds at body temperature compared to some synthetic rubber blends or thermoplastic polyurethane (TPU) alternatives. Many competitors (Fitbit, Garmin, Apple) also use silicone for sport bands with similar disclosure profiles. The main trade-off is durability and grip; some users report silicone can become tacky or degrade after 1-2 years of heavy use, but this is a physical wear issue, not a chemical safety issue.
If you buy it
Clean the bands regularly with mild soap and water to prevent bacterial growth, especially if worn during exercise or swimming. Avoid prolonged exposure to direct sunlight, high heat (above 60°C), or harsh solvents, which can accelerate silicone oxidation and surface cracking. Replace the bands if they become visibly cracked, torn, or sticky; these are signs of material degradation and may indicate loss of structural integrity. Store unused bands in a cool, dry place away from UV light to extend shelf life.
What we don’t know
- Basis
- Model estimate, 72% confidence, not a lab result
- Lab test
- None on record for this exact product
- Brand statement
- Withings has made none
Formulations change between production runs, so check the current label. How we grade.
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.