Rambler 12-Ounce Travel Bottle

We bought new travel bottles because the gaskets on our commuter lids are starting to be difficult to get a good seal. Since buying only the gaskets was not an option, and since the cost of buying all new cups seemed a better deal than just buying new commuter lids, we bought new cups. We were surprised that the design has changed, and weighing the cups revealed that there is less metal in the new than the old. Also, the bottom no longer has a slight recess - it's completely flat now, which makes us wonder if the new bottles will lose heat more quickly through the base. We don't know how to confirm or disprove that theory, and we haven't used the new bottles yet. The new bottles are tapered at the bottom which might make them a bit more comfortable to hold. I'm submitting this review now because I keep getting emails to do so.