Foam Insulated Travel Mug GS1500TRI6 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.

Thermos Foam Insulated Travel Mug GS1500TRI6

Thermos

Foam Insulated Travel Mug GS1500TRI6

PFAS grade

Excellent 85/100

Overall grade

Good 73/100

Verdict

Buy

Hazard flags

⚑ 3

Material

Stainless steel interior, foam insulation outer shell

Confidence

72%

PossibleFoam insulation degradation

PossibleAdhesive or flame retardant residues in foam

PossibleBacterial colonization in crevices

Our pick

THERMOS Stainless Steel King Travel Mug

Thermos

Stainless Steel King Travel Mug

PFAS grade

Excellent 95/100

Overall grade

Excellent 83/100

Verdict

Buy

Hazard flags

⚑ 3

Material

Stainless steel interior and exterior, plastic lid

Confidence

82%

PossiblePlastic lid polymer degradation

PossibleGasket/seal material composition

PossibleThermal shock stress on seals

Where these two actually differ

  • We flag Foam insulation degradation, Adhesive or flame retardant residues in foam and Bacterial colonization in crevices on the Thermos 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 Thermos.
  • The Thermos is Stainless steel interior, foam insulation outer shell 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