Originally, TracFone service was limited to TracFone-branded phones, which are locked to the TracFone service using an internal SIM card. Other GSM phones, even those that were unlocked from another carrier, could not accept a TracFone SIM card, because these are bound to a specific handset. However, in 2013, TracFone unveiled Bring Your Own Phone, and began selling SIM cards that could be inserted into qualifying non-TracFone phones (such as Verizon CDMA phones) to register them with TracFone. In 2015, this program was extended to compatible unlocked GSM phones and renamed "Bring Your Own Phone".