You can use the A1 smart watch to make or answer calls. The watch's built-in speaker allows you to listen to your favorite music anywhere. Bluetooth Dialer,Pedometer,Sleep monitor,Sedentary Reminder,Music Player,Alarm Clock, Watch,Camera,Remote camera,Bluetooth SMS/Message Notifier,Message Reminder,Call Reminder,Answer Call,Dial Call,NFC for quick pairing. Sync function: whats app, Twitter,Facebook;time,schedule,read message or news;Entertainment: ,Camera.Bluetooth connection support ninety nine percent of mobile phone market samsung,HTC,Nokia,Motorola, most have bluetooth function and mobile phone can use. Shut down automatically, The charge time need 1-2 hours, This product only work in 2G SIM and without I pin security it work.Once the Sim is inserted in the Sim slot it needs to be activated by the service provider.