Looking For Your Solar Panel Advice

So last year walking through GA I saw a couple cars had solar panels on their dashboards, soaking up the sun's rays under the windshield. They were big enough to take up the whole dashboard, so not portable. I'm assuming they were there to charge phones/lights/external battery packs.

Has anyone bought one of these before? I'm ignorant to the world of solar panels. Do they make them USB compatible, or should I expect to need an adapter or something? Thanks in advance