Contactless EMV cards have two interfaces (contact and contactless) and work as a normal EMV card via their contact interface. The contactless interface provides similar data to a contact EMV transaction, but usually a subset of the capabilities (e.g. usually issuers will not allow balances to be increased via the contactless interface, instead requiring the card to be inserted into a device which uses the contact interface). EMV cards may carry an "offline balance" stored in their chip, similar to the electronic wallet or "purse" that users of transit smart cards are used to.