This specifies whether a device is capable of holds two SIM cards. The two main types of dual-SIM phones are active and standby. Dual-SIM Standby (DSS) requires the user to define which of the two SIMs is able to make and receive calls, while Dual-SIM Active (DSA) enables both cards to receive calls at the same time. This latter feature usually requires an further transceiver for the secondary SIM card, and as such drain more battery life. More recent models feature Dual SIM Dual Standby (DSDS) technology which enables them to have two active SIMs with only one transceiver.