This silicone “У” (pronounced /-U/) sign means “Student driver.” It easily sticks to any smooth surface, such as windows, mirrors, screens, walls, message boards, dash boards etc. Please note that just like in English you find the letter U in a middle of “student” and in another particularly popular 4-letters word, the Russian letter У works exactly the same way, which is the whole point here.
This sign does not have any adhesive, therefore leaving no residue behind. To reuse it, simply peel off and reapply. If needed, you can wash it with water.