<P> Anti-lost keychains can easily locate a smartphone through the GPS and Bluetooth low energy antennas of the phone . Once the user is near the range of the smartphone, both the smartphone and device will alert the user . It also can be used to remotely take photographs using Bluetooth . </P> <P> Phone charms are used to decorate the device . They attach either by a strap or by plugging into the jack plug . </P> <P> Some smartphones feature SD card slots (usually the smaller Micro-SD variant). These, in combination with a compatible SD card, can be used to transfer files from one device to another, or simply to increase the storage capacity of the phone . </P> <P> Wi - Fi SDs are Wi - Fi communication devices on a special SD card inserted into the SD card slot . They can move pictures to a local computer or an online photo - sharing service . </P>

When was the first cell phone case invented