It's called a hot water dispenser. It keeps the water inside it at a constant temperature, so you can instantly pour hot water for your tea and coffee whenever you want.
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It is easy to go down into Hell;
Night and day, the gates of dark Death stand wide;
But to climb back again, to retrace one's steps to the upper air –
There's the rub, the task.
– Virgil, The Aeneid (Book VI)