24oz Tumbler with Straw 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
24oz Tumbler with Straw
PFAS grade
Overall grade
Verdict
Hazard flags
Material
Confidence
PossibleBPA/BPS and plasticizers in lid and straw
PossibleMicroplastics from plastic degradation
ReportedRubber gasket degradation and mold growth
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 BPA/BPS and plasticizers in lid and straw, Microplastics from plastic degradation, Rubber gasket degradation and mold growth and Lid printing or coating adhesion 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 Stainless steel double-wall with plastic lid and straw where the Thermos is Stainless steel interior and exterior, plastic lid, which is most of the difference in these two grades.
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