Clankers

"Ron passed the bag to Griphook and the goblin pulled out a number of small metal instruments that when shaken made a loud ringing noise like miniature hammers on anvils." Clankers are magical items which make a loud noise when shaken in a bag and are used in Gringotts Wizarding Bank.

They are small objects kept in a leather bags and when shaken emit a loud noise.

They are used in high-security to ward off the dragons guarding them. The dragons associate the sound of the Clankers with pain and so flee the vault that they are guarding when they hear the sound. They are used by the goblin employees at Gringotts in order to access certain vaults.

In 1998, Harry Potter, Ron Weasley, Hermione Granger, Griphook and Bogrod (who was Imperiused at the time) used the Clankers to ward off the dragon guarding the Lestrange Vault, in order to rob the vault.

Appearances
Harry Potter and the Deathly Hallows