How would you love to switch carrier on one sim? The Apple SIM

Apple has built a SIM card that lets you switch carrier network between AT&T, Sprint, and T-Mobile without having to swap it out purchase a new SIM card.

Instead of swapping the card, you just pick a new carrier through the device's on screen settings.

According to a page about the iPad Air 2's wireless connectivity, Apple calls the new SIM-"Apple SIM."

The Apple SIM gives you the flexibility to choose from a variety of short-term plans from select carriers in the U.S. and UK right on your iPad. So whenever you need it, you can choose the plan that works best for you — with no long-term commitments. And when you travel, you may also be able to choose a data plan from a local carrier for the duration of your trip.

The Apple SIM is not available for separate sale as it comes of the box in the cellular-enabled iPad Air 2.
This one SIM is currently compatible with AT&T, Sprint and T-Mobile in the U.S., and EE in the UK. The list will increase in time as other carrier networks join in the service.