Stainless King Tumbler vs Stainless Steel Travel Mug Zojirushi: 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 Steel Travel Mug Zojirushi
PFAS grade
A 95/100
Overall grade
C 77/100
Verdict
Buy
Hazard flags
⚑ 3
Material
stainless steel interior, plastic lid
Confidence
82%
PossiblePlastic lid and seal degradation
ReportedBacterial biofilm in lid threads and seals
PossibleThermal shock cracking of double-wall seal
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