Uguard.me's adhesive skins provide a more svelte alternative to bulky cases for protecting your phone. But they're also made with a special resin material that's slightly sticky to the touch. So they provide a bit of extra grip in the hand, and will actually stick to a smooth surface like a window.
Here's the kicker, though. The skin doesn't hold indefinitely. So while you could stick your phone to your car's window for some hands-free GPS navigation, it would only be a matter of time before it lost its grip and fell off. So it's best to think of these skins as a game of Cupertino Roulette that could end up costing you a lot more than just $20.