We'd advise a longer chain due to the locket's weight. The locket is sold independently of chain to allow you to choose your ideal length, but the bail is included. Due to the Size of the locket it is suited to a longer slightly heavier chain such as the Marina chain, whereas the Ball chains and other pendant chains may not be strong enough to hold it.
The majority of our standard charms do fit into the locket, but please note there are a few exceptions such as the Eiffel Tower Charm. A special bail comes with the locket so that if you do not wish to put a charm inside, it can also be worn on its own.