SPI.This A1 Smart Watch from SPI. will the most useful and fashionable accessory you will have. It has 1.54" IPS LCD radian capacitive touch screen for easy operations. Also has built-in SIM card and TF card slot. Works in 2G GSM 850/900/1800/1900 MHz Network. You can insert SIM and send and read texts, make or receive calls on your smart watch. Without SIM card, it works as a cell phone companion, receiving and making calls, getting texts via Bluetooth. It has functions like: Bluetooth Dialer, Pedometer, Sleep monitor, Sedentary Reminder, Music Player, Alarm Clock, Watch, Camera, Remote camera, Bluetooth SMS/IM Message Notifier, Message Reminder, Call Reminder, Answer Call, and Dial Call. Has: MP3, MP4, Camera.