Sea to Summit · Waterproof Smartphone Cases
SEA TO SUMMIT TPU Guide Waterproof Case for iPhone Black 358BK
Waterproof case with unspecified coating; PFAS risk unclear without disclosure.
Sea to Summit does not publicly disclose PFAS content or water-repellent coating treatment chemicals in this TPU phone case. Waterproof products often use PFAS-based coatings, but brand transparency is absent here.
The safe swap
Mophie
Mophie Juice Pack Battery Case for iPhone 15
85/100 safety
Still want this one anyway? Check the price on Amazon. We’d swap it.
Material
TPU (thermoplastic polyurethane) with waterproof coating
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Waterproof / stain-resistant treatment
water-repellent coating treatments have historically used PFAS.
Category baseline
other is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
The full breakdown
What it's made of and why it matters
This case is constructed from TPU (thermoplastic polyurethane), a flexible synthetic rubber polymer that is inherently resistant to water and abrasion. TPU itself is chemically inert at normal use temperatures and does not off-gas volatile organic compounds under standard conditions. The waterproof performance likely relies on a coating or lamination layer, Sea to Summit does not specify whether this uses Teflon-type coating, silicone, polyurethane, or another polymer. Without transparency on the waterproofing agent, PFAS presence cannot be ruled out, though TPU substrate alone poses minimal chemical leaching risk.
The brand's record and disclosure
Sea to Summit is an outdoor equipment brand known for durable, functional gear; they do not publish material safety data sheets or PFAS-avoidance certifications for this product line. The company has not issued public statements on PFAS use or phaseout timelines. No recalls or documented safety incidents are on record for this specific case. The lack of disclosure is a gap rather than evidence of harm, but limits independent assessment of waterproof coating composition.
How it compares in its category
Waterproof phone cases compete on seal integrity and material durability; TPU-based designs are a mainstream choice alongside silicone and rigid polymer alternatives. Most competitors similarly avoid chemical ingredient transparency, making this case typical in its opacity rather than exceptional. Cases using Teflon-type coating-based water-repellent coating (water-repellent coating) coatings are common across the outdoor gear sector; TPU does not require such coatings for basic water resistance, yet many manufacturers still apply them for enhanced performance.
If you buy it
Keep the case away from prolonged heat above 60°C (140°F), as TPU can soften and any coating may degrade. Inspect regularly for tears, cracks, or seal degradation; discard and replace if the case loses structural integrity or shows visible wear at seams, as waterproofing will fail. Wash with cool water and mild soap, then air-dry; avoid dishwasher or boiling. Do not apply heat-based adhesives or solvents to repair seams, as these can compromise the material bond.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
Waterproof coating composition (unspecified)
Sea to Summit does not disclose whether the waterproofing layer uses fluorinated compounds (Teflon-type coating, C6/C8 PFAS) or non-fluorinated alternatives. PFAS presence in water-repellent coating coatings is common in the outdoor gear sector, but cannot be confirmed for this product without manufacturer data.
TPU thermal degradation
Prolonged exposure to heat above 70°C can cause TPU to soften, discolor, or release minor volatile degradation products. Phone use itself does not typically generate such heat, but sauna or car-dashboard storage could trigger this.
Microplastic shedding from mechanical wear
Long-term abrasion and flexing of TPU cases can generate microplastic particles at seams and contact points. Environmental release is minimal if the case stays intact, but visible cracking or peeling warrants replacement.
Seal failure and contamination entry
If the waterproof seal degrades (typically at zipper tracks, glued seams, or pinch points), water can enter and potentially corrode phone internals or harbor bacterial growth inside the case.
Fragrance additives or plasticizers in TPU
No fragrance or phthalate plasticizer presence is documented in TPU phone cases. Industry standard TPU formulations for phone accessories do not routinely incorporate these, though some lower-cost brands may use unregulated suppliers.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 45% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
Safer alternatives in Waterproof Smartphone Cases
Mophie
Juice Pack Battery Case for iPhone 15
Lithium-ion battery, plastic housing, metal contacts
No known PFAS use; battery cases rarely require fluorinated coatings.
⚠Brand says nothing about PFAS
Mophie
Juice Pack Battery Case for iPhone 15 Pro
Lithium-ion battery, plastic housing, rubber grips
Lower concern. Battery cases lack typical PFAS-prone coatings; no public disclosure available.
⚠Brand says nothing about PFAS
Pelican
Shield Phone Case for Samsung Galaxy S24 Plus
Polycarbonate shell, rubber grip
Lower concern; typical phone case with no known PFAS applications.
⚠Brand says nothing about PFAS
More waterproof smartphone cases 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.