When Harry returned to his room that night, his trunk was at the foot of his bed; on top of it was a pair of heavy silver keys on a ring. Unlike a Muggle keyring, this one was a loop of solid silver, but when he touched his Gringotts key to the metal, it passed through the ring as though it were smoke. Harry added the keys to his bedroom and the front door of Number Four to the ring, too, before turning the first of the silver trunk keys in the trunk’s lock. 