How The Unlocked Feature Works in The U.S.- 1) With this device, you do not have to use the Apple SIM card in order to get cellular service. To activate with your cellular carrier, all you have to do is purchase a SIM card from that carrier. This iPad is completely unlocked and will work on any network that can provide a SIM card (except Verizon). Most Verizon stores will only activate iPads bought from them. Check with your local Verizon rep if you intend on using their service. 2) If you want to activate your cellular service using the Apple SIM card (already in the device), the options of carriers for the Apple SIM Card will be displayed directly on the device once you set up and begin using your Ipad. The Apple SIM card will allow you to activate the iPad with Sprint, AT and T, or T-Mobile. Just a few clicks and your cellular service will be ready for use. Verizon chose not to participate in the Apple SIM card program. How The Unlocked Feature Works Outside The U.S. -This Ipad is completely unlocked. It will work with any carrier. All you have to do is purchase a SIM card from any local carrier and install it into the SIM card slot. You can also use the Apple SIM card (included) in some countries. Every country has different participating providers that connect via the Apple SIM card. The options of carriers for the Apple SIM Card will be displayed directly on the device (if carriers available in area) once you set up and activate the Ipad. Then with just a few clicks, your cellular service should be ready for use.