COMPATIBILITY - Samsung?? HTC?? Sony?? LG?? HUAWEI?? ZTE?? OPPO?? XIAOMI(for iphone?? this APP can' t be installed by iOS?? Our watch can only receive and make call after connect with iphone. Other functions are u" now for iphone!)</br>MAIN FUNCTIONS - It runs Facebook?? Twitter independently when you put SIM card and TF card in this watch. This watch Also have Pedometer?? alarm clock?? sleep monitor?? sedentary remind?? calendar?? calculator?? voice recorder?? MP3?? muti-timezone?? muti-language?? daylight saving time.</br>USE AS A INDEPENDENT PHONE - If put SIM card in the watch?? you can make phone call directly from the smart watch??including answering and dial