Raise your hand if you are still in search of the perfect mug. You know, one that will keep your tea/coffee/whatever at the temperature you want without having the messy spillage that inevitably occurs no matter how careful you are. Now, consider the elegance of this particular double walled porcelain mug, with its sliding lid and accompanying drip filter, and if it would solve your beverage issues enough to justify the cost.
Holds 10 fluid ounces (310 ml).
3.5″ dia. x 6.7″ high
Also, see the Lotus Tea Cup for similar sliding lid magic.