40 oz Stainless Steel Traveler vs Stainless Steel King Travel Mug: which is safer?
THERMOS Stainless Steel King Travel Mug is our pick: better on PFAS and on the overall hazard picture.
S'well
40 oz Stainless Steel Traveler
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossiblePlastic lid additive leaching (BPA/BPS/phthalates)
LikelyPlastic lid degradation over time
PossibleLid seal integrity loss
Our pick
Thermos
Stainless Steel King Travel Mug
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossiblePlastic lid polymer degradation
PossibleGasket/seal material composition
PossibleThermal shock stress on seals
Where these two actually differ
- We flag Plastic lid additive leaching (BPA/BPS/phthalates), Plastic lid degradation over time and Lid seal integrity loss on the S'well and not on the Thermos.
- We flag Plastic lid polymer degradation, Gasket/seal material composition and Thermal shock stress on seals on the Thermos and not on the S'well.
- The S'well is 18/8 stainless steel interior and exterior, plastic lid components where the Thermos is Stainless steel interior and exterior, plastic lid, which is most of the difference in these two grades.
- These two are level, close enough that price and fit should decide it rather than our grade.
Both products run through the same public rubric: materials, coatings, brand disclosure, lab findings, and recalls, plus a beyond-PFAS hazard analysis. Grades are model-based estimates, not lab tests. How grades work →
More insulated travel mugs: see the full ranking