There's the button that unlocks the car's doors and the one that pops the trunk. And then, on some BMWs, the key fob has a button with a diamond on it.

This short video will show you how the BMW Display Key works, with a small guide to its basic functions included ...

Here are 15 functions that modern key fobs are capable of accomplishing at the push of a button ...

Some key fobs have many features built in that owners may not even be aware of. Here's our guide to hidden key fob features.