Micro SIM are supported. Verizon and Sprint CDMA SIM are not supported. This watch works likes a 2G mobile phone. Please make sure the SIM card you buy works on 2G devices. This watch only supports GSM SIM with 2G GPRS date. 3G UMTSHSPA+4G LTE networks are not supported. If necessary, check with the carrier if GSM 8501900 MHz is supported. Features APP system requirements: Android 4.0 system or more, IOS 8.0 or above Touch Screen: 1.44" TFT Touch Screen Touch Screen: Capacitive Touch Screen SIM card: supported, 2G SIM card,85090018001900 Small flashlight for viewing in dark places SOS button for emergencies Built-in camera Learning games for kids to play Remote monitoring for keeping a safe watch on your children Built-in microphone for two-way communication Battery: environmentally friendly 400 mA polymer battery LBS positioning Parents can customize a security range that alerts when the watch is moved beyond that location Enabledisable functions according to time Trace replay can track movement for up to 30 days Strangers cannot call the watch Alarm clock reminders Friends function allows pairing and voice chat with friends Low power warning Remote power off Package:1x smart watch We warrant that the products comply with all applicable laws, and are offered only if they comply with Joom's policies and EU Product Safety and Compliance laws.