<Table> <Tr> <Td> </Td> <Td> The examples and perspective in this article may not represent a worldwide view of the subject . You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate . (January 2010) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> The examples and perspective in this article may not represent a worldwide view of the subject . You may improve this article, discuss the issue on the talk page, or create a new article, as appropriate . (January 2010) (Learn how and when to remove this template message) </Td> </Tr> <P> A key is a device that is used to operate a lock (such as to lock or unlock it). A typical key is a small piece of metal consisting of two parts: the bit or blade, which slides into the keyway of the lock and distinguishes between different keys, and the bow, which is left protruding so that torque can be applied by the user . A key is usually intended to operate one specific lock or a small number of locks that are keyed alike, so each lock requires a unique key . The key serves as a security token for access to the locked area; only persons having the correct key can open the lock and gain access . Common metals include brass, plated brass, nickel silver, and steel . </P> <P> Keys provide an inexpensive, though imperfect, method of access control for access to physical properties like buildings, vehicles and cupboards or cabinets . As such, keys are an essential feature of modern living, and are common around the world . It is common for people to carry the set of keys they need for their daily activities around with them, often linked by a keyring, which may be adorned by trinkets, usually known as a keychain . </P>

What is the top part of a key called