Best in segment Display, Touch, Chipset and Working memory (Compared to all products in this segment). Compatibility: All Android and iOS Mobile Phone & Android Tablet PC. Android Mobile Phone: Samsung, HTC, Sony, LG, HUAWEI, ZTE, OPPO, XIAOMI, and so on. iOS Mobile Phone: iPhone 6, iPhone 6 plus, iPhone 5, iPhone 5s , iPhone 4, iPhone 4s (This APP can' t be installed by iOS, Apple system can' t sync SMS and Bluetooth push information, but other functions can be used by iPhone). Sync function: QQ,wechat,Twitter,Facebook,time,schedule,read message or news. Sport health: Pedometer,sedentary remind,sleep monitoring.? Phone function(GSM and 2G only): Make phone call directly from the smart watch,including answering and dial-up.SIM slot,support make calls by Bluetooth or smart watch.