Stainless King Tumbler vs Stainless Carry Tumbler: which is safer?
Stainless King Tumbler is our pick: better on PFAS and on the overall hazard picture.
Our pick
Thermos
Stainless King Tumbler
PFAS grade
A 95/100
Overall grade
A 91/100
Verdict
Buy
Hazard flags
⚑ 1
Material
Stainless steel interior, plastic exterior lid
Confidence
78%
PossiblePlastic lid degradation and leaching
Zojirushi
Stainless Carry Tumbler
PFAS grade
A 95/100
Overall grade
C 77/100
Verdict
Buy
Hazard flags
⚑ 3
Material
Stainless steel interior, plastic exterior
Confidence
78%
PossibleStainless steel interior corrosion or nickel release
PossibleSeal integrity and bacterial growth in lid
ReportedThermal shock or seal failure from extreme temperature swings
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 drinkware tumblers: see the full ranking