The TechComm GSM unlocked GV18 smartwatch will keep you up to date with your notifications, text messages and daily reminders. Connect it with your phone via Bluetooth or use a GSM Micro SIM card to make phone calls directly from the watch. The GV18 will also serve as your personal health monitor with sleep monitor, fitness tracker, pedometer and calorie counter. Soft rubber strap ensure comfort for everyday use. All functions support IOS & Android Smart Phone Call synchronization. Disclaimer: this is a Bluetooth smartwatch and all functions can be used by pairing with a smartphone. If you want to use the watch as a stand-alone phone, a GSM SIM Card is required. This watch is not compatible with CDMA networks (including Sprint and Verizon). If you are a Sprint or Verizon customer, you can still connect the watch to your phone via Bluetooth. Insert an activated GSM Micro SIM card from any GSM carrier in the USA or abroad, such as T-Mobile, AT&T, H20, Metro PCS, Prepaid GSM carriers, etc. Note that the watch supports calls and SMS only (no data).