3G & 4G data cards (aka "aircards" or "modems") allow you to get online via cellular internet service (also referred to as "mobile broadband"). Mobile broadband works similarly to the way your cell phone operates in that it relies on signal from a wireless tower rather than a physical connection like a phone line or cable. A 3G or 4G data card receives the signal and allows you to connect to the internet - it's as simple as that! Select the carrier you're interested in to view products for that provider.
New to mobile broadband? Start here: Mobile Broadband Basics
Need to see which provider has the best coverage where you need it? Check the Coverage Maps