CS COSDDI Stainless Steel Insulated Tumbler

Absolutely, and it's genuinely good at it. The vacuum insulation works both ways — reviewers confirm it keeps cold drinks iced for extended periods, and the outside stays condensation-free so it won't sweat all over your desk or bag. An unexpected bonus that several reviewers discovered: the screw-on lid actually holds ice back when you pour, making it double as a cocktail or mocktail shaker. It even retains carbonation better than some other containers if you're into sparkling iced tea.

For most people, yes. Twelve ounces is a standard coffee cup serving, and it's the perfect amount for a commute drink without being bulky. The compact size is actually an advantage — it fits cup holders, slides under Keurigs, and is easy to carry. That said, if you use the largest Keurig brew setting, a couple of reviewers noted it can overflow the 12 oz capacity. And if you're a 'big gulp' coffee drinker who needs 20+ ounces, you'll want something larger. But for tea especially, 12 oz is a very natural serving size.

Eight reviewers specifically praised how easy it is to clean, which matters a lot for tea drinkers since tannins can stain quickly. The wide mouth lets you get a bottle brush inside without struggling, and the stainless steel interior doesn't absorb stains or odors the way plastic does. One thing to note: several reviewers recommend giving it a thorough cleaning before first use — a good soak with baking soda and warm water will do the trick. After that, daily cleaning is straightforward.

Daily commuters and office workers who want a reliable, affordable tumbler that just works. It's perfect if you brew at home (especially with a Keurig — it fits right underneath), drive to work, and want your drink still hot when you arrive. The simple screw-on lid design makes it beginner-friendly, and it's forgiving enough to switch between hot tea, iced coffee, and even beer without retaining flavors. It's not ideal if you have very small hands (some find the grip too wide), need to frequently open and close the lid one-handed, or want a tumbler that lasts through years of heavy daily use.

Surprisingly, yes. Several reviewers discovered you can steam milk directly in the cup for lattes, which is a creative use the manufacturer probably didn't intend. The stainless steel interior handles the heat well and doesn't impart flavors. It's not going to replace a proper frothing pitcher, but for a quick homemade latte on the go — steam your milk, add espresso, screw on the lid, and head out — it works better than you'd expect for the price.

It's functional but not the tumbler's strongest feature. The flip-top design works fine for sipping, but four reviewers found it can be tricky to close or reopen once locked. It's not a dealbreaker — you get used to the motion — but if you're someone who opens and closes their tumbler lid constantly throughout the day with one hand, it might frustrate you. For a typical commute where you open it, sip during the drive, and close it when you arrive, it's perfectly fine.

Look for three things: insulation quality, leak-proofness, and size. The CS COSDDI checks all three — its vacuum insulation keeps tea hot for hours, the screw-on lid is spill-proof when properly sealed (great for tossing in a bag), and at 12 oz it fits standard cup holders without being bulky. If you brew tea that needs steeping, you'll want a separate infuser since this tumbler doesn't include one. But for pre-brewed tea on the go, the stainless steel interior is a plus — it won't retain flavors or odors between different teas, which plastic tumblers often do.

It depends on what you're prioritizing. The CS COSDDI offers solid temperature retention — reviewers confirm it keeps hot drinks warm for 1-3+ hours and cold drinks iced for extended periods — at a fraction of Yeti's price. Multiple reviewers specifically call out the excellent price-to-value ratio. Where it falls short compared to premium brands is long-term durability: some users report paint chipping and gasket issues after 4-7 months of daily use. If you want a reliable everyday tumbler without the premium price tag, it's a strong pick. If you need something that'll last years of heavy abuse, you might want to invest a bit more.

The CS COSDDI doesn't come with a built-in infuser, but its wide mouth makes it easy to use a separate basket-style tea infuser that sits inside the tumbler. Just steep your tea, remove the infuser, and screw the lid on for a leak-proof commute. The stainless steel interior is actually ideal for this — it won't absorb tea flavors or stains the way some materials do, so you can switch between green tea in the morning and chai in the afternoon without flavor carryover.