I have lost count of how many insulated cups i have owned over the years, and to be honest they were all shite, for a variety of reasons. Mostly that they were unable to keep a cup of tea hot for more than a hour. Some were poorly designed so that they wouldn’t fit a standard cup holder, some were top heavy & would fall out of a cup holder at the slightest touch of the brake or accelerator. But now I have found the perfect Thermos mug. Fill it with hot tea at 11am and then drive to a football match, still too hot to drink, 2pm still very hot. 5pm still hot enough to drink.
Not the cheapest Thermos mugs available but certainly the best I have found so far. Also as long as the lid is closed you can put it in a bag without fear of it spilling.