Bluetooth Smart Watch Unlocked Cell Phone Watch with SIM Card Slot Smartwatch for Samsung LG HTC Sony Google Huawei Xiaomi Android Smart Phones (Black) STAND ALONE MODE: Designed to be used independently without the need of a smart phone, thanks to its Nano SIM card capability. Simply place a GSM Nano Sim card in the slot provided. You can send and receive calls, texts, messages etc directly on the smart watch. We recommend the T-mobile GSM SIM card and Speedtalk GSM SIM card. BLUETOOTH MODE: This feature allows you the option of not using or purchasing a separate Sim Card. Simply connect to the smart watch via Bluetooth with your Android device. Bluetooth connection supports making and answering calls, receiving texts, as well as supporting message and notifications from other APPs such as Facebook, Twitter, Whatsapp, Wechat etc. MAIN FUNCTIONS: Make calls and Answer calls, Send and view messages, sync calls, sync messages, notifications (for Facebook, Twitter, Wechat, Whatsapp etc), pedometer, sleep monitoring, sedentary remind, Image viewer, Sound recorder, Audio player, Remote capture, Alarm, Two way Anti-lost, Phone book, calendar, calculator. (Note: a TF memory card is needed to support image viewer, sound recording and Audio Player). MAXIMUM COMPATIBILITY: This smart watch is compatible with all Android devices and IOS Devices. It is 100% compatible with all Android smart phones. Please Note: There is no App for iPhone, resulting in the following features being inaccessible: Messaging, notifications, remote capture, Phonebook, call logs, BT music and Anti lost. HD Display: Full round screen smart watch, high sensitive capacitive touch screen, Perfect match technology, Resolution ratio: 240*240. 1 year quality warranty and 24 hours email service. If you have any issues or confusion on pairing process with our Android phone, please ask us for help.