We have several Swell products and love them all. We even had a semi-scientific side-by-side comparison withe a neighbors YETI product and the Swell product was almost 20 F warmer after three hours so that neighbor bought a Swell.

I bought a Swell Traveler for morning coffee in the car and IT IS NOT AS THERMALLY EFFICIENT AS MY OTHER SWELL PRODUCTS.

A side-by-side test against those other product shows a 17 F difference after three hours, which is identical to all the other similar Thermous and Yeti products we have.