Official Harry Potter Platform 9 3/4 Keyring Platform 9 3/4 Keyring on a silver plated ring and clip This keyring has been created using the official style guide from Warner Bros. They are approx 50mm. It comes on official Harry Potter branded card packaging and shows the Warner Bros logo on the reverse. The Carat Shop are the official licensed manufacturers of Harry Potter Jewellery on behalf of Warner Bros. Official Harry Potter Platform 9 3/4 Keyring Platform 9 3/4 Keyring on a silver plated ring and clip The Platform at Kings Cross Station in which Hogwarts Students gained access to the Hogwarts Express This keyring has been created using the official style guide from Warner Bros. They are approx 50mm. It comes on official Harry Potter branded card packaging and shows the Warner Bros logo on the reverse.