thermal tumbler

Common capacities shown include 14 ounces, 18 ounces, 30 ounces, and 40 ounces.

Most thermal tumblers are made from stainless steel—often specified as 18/8 food‑grade (sometimes recycled 18/8)—and many listings also note BPA‑free construction.

Most tumblers use double‑wall (dual‑wall) vacuum insulation. A few listings mention triple‑layer insulation or a copper‑coated inner wall for added insulation.

Many tumblers are designed with narrow bases to fit most car cup holders. Several models also include handles or comfort‑grip features to make them easier to carry.

Reviewers commonly praise long thermal retention and generally good spill resistance, though a minority report lid or straw leaks and occasional lid issues.