Genuine 1916-D "Mercury" dimes are one of the great and famous rarities of the American coinage series. They are, of course, the same size as regular dimes.
This piece has "COPY" stamped on it to comply with the Hobby Protection Act; it is illegal in America to publicly sell or import replica coins that are not so marked. One could perhaps argue that a replica "coin" with the design of a dime but the size of a silver dollar did not technically need the stamp, since it "obviously" wasn't a real dime, but the makers/sellers of this object decided to play it safe and include it.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis