: High-end models feature airtight polymer seals and non-drip lids, making them leak-proof and spill-resistant. This is a massive upgrade over an open-top bottle that can easily tip over in a car.
: Stainless steel internals make these very easy to clean under running water, though some users find that disposable liners are necessary to completely avoid the "gross factor" of rinsing it out. mature spitting tube
, are designed to look like a standard coffee tumbler. This allows for "stealth mode" in public without drawing unwanted attention. : High-end models feature airtight polymer seals and