YINJOYITravel Mug Reusable Coffee Cups Thermal Insulated Vacuum Insulation Stainless Steel Bottle for Hot Cold Drinks(White, 510ml)

This cup does all that I wanted.Good size but still fits into the car cup holder. Leakproof when shut properly and definitely keeps my my morning coffee warm. So much so that I have to leave it open to cool down enough to drink.

Actually does keep drinks hot for ages. Leave the lid off and the drink is still hot for around an hour (depending how hot you like it) lid on - minimum of 3 hours and I work outdoors a lot keeps hot drinks HOT

What a mug! Looks great, doesn’t leak, keeps drinks hot.Only negative is that it isn’t dishwasher safe.

I bought this to use on dog walks. In the winter it keeps your drinks hot and in the summer, your drinks cold. Easy to hold, carry and hand wash. Excellent quality too.

Nice mug. Keeps hot for as long as I need it.

Works surprisingly well! Leakproof. Keeps hot for a couple hours. Love the colour! Very sturdy too.

I'm not a fan of "design features" that don't add functionality, and most coffee chain shop mugs fall into that lamentable category. They have fancy body shapes, handles, and strange lids, that don't add anything to the mug.It keeps the drink warm for a respectable amount of time - it's a large volume, so a regular fill will only come to about 2/3 of the capacity which makes it less prone to spilling.The "serrated" section is a silicone wrap that can be taken off for cleaning, the lid screws in and has a silicone O-Ring seal. There's a flap on the lid that push-clicks into place to seal the drinking hole, (and covers the air-inlet whole) and clicks open in the opposite direction.The lid is leak proof enough - in the sense that walking vigorously won't spill the content, or if it cup is knocked over with the lid screwed on and closed, but not well enough that you could toss the full cup into a bag/backpack and hope your laptop will survive. It might, it might not. It's a cup, not a flask.Highly recommended, simple, functional design.The inside of the cup is brushed steel, which can mildly stain with use, so a scouring pad is needed if you want to keep it sparkling as new. There's an embossed marking at the bottom of the cup where a bottle brush or similar may be needed as you may get a bit of coffee/tea stain build-up around the lettering.

I bought 4 different makes of these travel/insulated cups/mugs, they all function pretty much the same, stainless steel double walled lining with some sort of either paint/laquer/plastic coating and all sorts of caps with different stoppers.None of them leaked when shaken up and inverted with hot liquid inside, but then i wouldn't expect them to as they are all brand new, only time and use will decide how resilient the seals are.In terms of heat retention (I wasn't interested in keeping drinks cold) I tested them all the same way, preheated each mug with boiling water and then poured 350ml of boiling water in, and sealed them.I can only say that the claims made by all the manufacturers that these devices keep dinks hot for hours is absolute twaddle and misrepresentation.Buyers who reviewed these mugs claiming that their drinks stayed hot for hours certainly have no understanding of the word “hot”After two hours the contents of all of the mugs had dropped in temperature to around 50-55c…that is not “hot” in the understanding of “hot” tea or coffee and reviewers are greatly exaggerating the performance of these mugs.If you make a hot drink like tea or coffee, it will be pretty much only warm after 2 hours.If you like your hot drinks hot you would need to consume them within an hour and a half or less for them to be reasonably described as “hot”.All of these type of dual walled stainless steel mugs, no matter what make or design…or price, are going to be around the same or worse performance, quite disappointing actually.I'm afraid if you want hot drinks to stay HOT for a few hours you will have to go back to the old fashioned Thermos flask situation, and by that I mean the glass walled Thermos & unfortunately they are prone to shattering if dropped or abused but they at least do what it says on the “tin’I really don't know why when buyers review these things they make wildly exaggerated claims about drinks being hot “hours” later, its just simply not true, if you like tepid tea and coffee, fine, I don't, hot drinks should be hot and cold drinks should be cold.