Hogwarts tea towel

"At least a hundred little elves were standing around the kitchen, beaming, bowing, and curtsying as Dobby led Harry past them. They were all wearing the same uniform: a tea towel stamped with the Hogwarts crest, and tied, as Winky's had been, like a toga."

- Description.

These tea towels were originally used to dry china tea service, although, they developed into the serviceable uniform of the Hogwarts house-elves, who wear it tied like a toga.

Appearances

 * Harry Potter and the Goblet of Fire
 * Pottermore